Previous Year Paper

RRB Technician Grade III Official Paper (Held On: 28 Dec, 2024 Shift 3) (Previous Year Paper)

Held in 2024

100 questions90 minutes
With answers
Free

Paper last updated:

Practise under exam conditions

Take this paper as a timed mock test. Review your answers after you submit.

Attempt timed test

Questions & answers

Read the paper at your pace. Open an explanation when you need it.

Full Test (100 questions)

Question 1

Cranial nerves arising from the brain and spinal nerves arising from the spinal cord together constitute the:

  1. AOption (a)

    peripheral nervous system

  2. BOption (b)

    central nervous system

  3. COption (c)

    autonomic nervous system

  4. DOption (d)

    endocrine system

View answer & explanation

Correct answer

Answer: (a)A.

peripheral nervous system

Why this answer is correct

The Correct answer is peripheral nervous system.

Key Points

  • The peripheral nervous system (PNS) consists of all the nerves that lie outside the brain and spinal cord.
  • It includes cranial nerves (arising directly from the brain) and spinal nerves (arising from the spinal cord).
  • The PNS is responsible for connecting the central nervous system (CNS) to the organs, limbs, and skin, enabling communication between the brain and the rest of the body.
  • It is divided into two main components: the somatic nervous system and the autonomic nervous system.
  • The somatic nervous system controls voluntary movements of skeletal muscles.
  • The autonomic nervous system regulates involuntary functions such as heart rate, digestion, and respiratory rate.
  • Cranial nerves like the optic nerve and olfactory nerve perform critical sensory and motor functions.
  • Spinal nerves are categorized into cervical, thoracic, lumbar, sacral, and coccygeal nerves based on their location in the spinal column.

 Additional Information

  • Central Nervous System
  • The central nervous system (CNS) includes the brain and spinal cord.
  • It is responsible for processing and interpreting sensory information and sending out instructions.
  • The CNS is protected by the skull and vertebral column, as well as cerebrospinal fluid.
  • Autonomic Nervous System
  • The autonomic nervous system is a division of the PNS that controls involuntary functions such as heartbeat, breathing, and digestion.
  • It is further divided into the sympathetic and parasympathetic systems, which work together to maintain balance in the body's functions.
  • Endocrine System
  • The endocrine system is not part of the nervous system but works closely with it.
  • It consists of glands that secrete hormones into the bloodstream to regulate processes like metabolism, growth, and reproduction.
  • Examples of endocrine glands include the pituitary gland, thyroid gland, and adrenal glands.

Question 2

Read the given statements and conclusions carefully. You have to take the given statements to be true even if they seem to be at variance from commonly known facts and decide which conclusion(s) logically follow(s) from the given statements.

Statements:

All roses are lilies.

No lily is a marigold.

Conclusions:

(I) All lilies are roses.

(II) No rose is a marigold.

  1. AOption (a)

    Only conclusion I follows

  2. BOption (b)

    Neither conclusion I nor II follows 

  3. COption (c)

    Both conclusions I and II follow

  4. DOption (d)

    Only conclusion II follows

View answer & explanation

Correct answer

Answer: (d)D.

Only conclusion II follows

Why this answer is correct

The least possible Venn diagram for the given statements is as shown below :

Conclusions:

(I) All lilies are roses → Does not follow (As all roses are lilies. So it is possible but not definite.)

(II) No rose is a marigold → Follow (As all roses are lilies and no lily is a marigold. As whole roses comes in lilies which cannot be marigold, therefore it is true)

∴ Here, Only conclusion II follows.​

Hence, the correct answer is "Option 4"

Question 3

Which of the following metals is most ductile?

  1. AOption (a)

    Sodium

  2. BOption (b)

    Lithium

  3. COption (c)

    Lead

  4. DOption (d)

    Gold

View answer & explanation

Correct answer

Answer: (d)D.

Gold

Why this answer is correct

The correct answer is Gold.

Key Points

  • Gold is the most ductile metal known to mankind, meaning it can be drawn into extremely thin wires without breaking.
  • It is possible to draw a single gram of gold into a wire with a length of approximately 2.4 kilometers.
  • The exceptional ductility of gold is due to its metallic bonding, where electrons are free to move, allowing atoms to slide past each other without breaking the structure.
  • Gold is widely used in electrical wiring, jewelry, and decorative items due to its ductility and other properties such as resistance to corrosion and excellent conductivity.
  • Its ability to be shaped into intricate designs makes it invaluable in industries such as electronics and aerospace.
  • Gold is also highly valued for its economic and cultural significance across the globe, often symbolizing wealth and prosperity.

 Additional Information

  • Sodium
  • Sodium is a highly reactive alkali metal and is not known for its ductility.
  • It is soft and can be cut with a knife, but its low melting point and reactivity make it unsuitable for applications requiring ductility.
  • Sodium is primarily used in chemical industries and in the production of sodium compounds like sodium hydroxide and table salt.
  • Lithium
  • Lithium is the lightest metal and is moderately ductile, but it does not compare to gold in terms of ductility.
  • It is widely used in batteries, especially in lithium-ion batteries, due to its high energy density.
  • Other applications include ceramics, glass manufacturing, and as a mood-stabilizing drug in medicine.
  • Lead
  • Lead is a soft and malleable metal, but it is far less ductile than gold.
  • It is primarily used in batteries (lead-acid batteries), radiation shielding, and in the production of alloys and pipes.
  • Lead has a high density and is toxic, limiting its use in certain industries.

Question 4

Which team won the Khelo India Para Games 2023 held in New Delhi in December 2023?

  1. AOption (a)

    Gujarat 

  2. BOption (b)

    Uttar Pradesh

  3. COption (c)

    Haryana

  4. DOption (d)

    Tamil Nadu

View answer & explanation

Correct answer

Answer: (c)C.

Haryana

Why this answer is correct

The Correct answer is Haryana.

Key Points

  • Haryana emerged as the champion of the Khelo India Para Games 2023, showcasing outstanding performances by its athletes.
  • The event was held in New Delhi in December 2023 and aimed to promote inclusivity and provide a platform for para-athletes to display their talent.
  • Haryana is known for its strong emphasis on sports and has consistently produced top athletes in various disciplines, including para-sports.
  • The state's para-athletes excelled in multiple events, contributing significantly to Haryana's overall medal tally.
  • The Khelo India Para Games is a part of the larger Khelo India initiative, launched by the Government of India to promote sports at the grassroots level and nurture young talent.
  • The event featured a variety of sports tailored to the abilities of para-athletes, including athletics, swimming, badminton, and wheelchair basketball.
  • Haryana's victory highlights the state's commitment to fostering sports infrastructure and providing support to athletes with disabilities.

 Additional Information

  • Gujarat
  • Gujarat is known for its initiatives in promoting sports, including hosting major events like the National Games of India 2022.
  • However, it did not secure the top position in the Khelo India Para Games 2023.
  • Uttar Pradesh
  • Uttar Pradesh has been actively working to enhance its sports infrastructure and has produced many talented athletes over the years.
  • While the state performed well, it could not surpass Haryana in the medal tally at the Khelo India Para Games 2023.
  • Tamil Nadu
  • Tamil Nadu has a rich history of supporting para-athletes and promoting inclusivity in sports.
  • Despite its efforts and participation, the state did not achieve the top spot in this edition of the games.

Question 5

At what rate (in percentage) per annum will ₹1,300 give ₹650 as simple interest in 10 years?

  1. AOption (a)

    8%

  2. BOption (b)

    5%

  3. COption (c)

    7%

  4. DOption (d)

    4%

View answer & explanation

Correct answer

Answer: (b)B.

5%

Why this answer is correct

Shortcut Trick

Total Simple Interest for 10 years is ₹650.

Interest for 1 year = 650 ÷ 10 = ₹65.

Rate % = (Interest for 1 year ÷ Principal) × 100

Rate % = (65 ÷ 1300) × 100 = 5%.

∴ The correct answer is 5%.

Alternate Method

Given:

Principal (P) = ₹1,300

Simple Interest (SI) = ₹650

Time (T) = 10 years

Formula Used:

Simple Interest (SI) = (P × R × T) ÷ 100

Calculations:

⇒ 650 = (1300 × R × 10) ÷ 100

⇒ 650 = 130 × R

⇒ R = 650 ÷ 130

⇒ R = 5%

∴ The correct answer is 5%.

Additional Information

Simple Interest Basics

Interest remains constant every year in Simple Interest. Total Amount = Principal + SI.

Effective Rate of Interest

Effective Rate for the entire period is R × T %. Here, 5% × 10 = 50%, which matches ₹650 being 50% of ₹1,300.

Relationship with Compound Interest

For the first year (or first compounding period), Simple Interest and Compound Interest are always equal.

Question 6

Which gas is primarily produced during the burning of coke?

  1. AOption (a)

    Nitrogen dioxide

  2. BOption (b)

    Carbon dioxide

  3. COption (c)

    Oxygen

  4. DOption (d)

    Sulphur dioxide

View answer & explanation

Correct answer

Answer: (b)B.

Carbon dioxide

Why this answer is correct

The Correct answer is Carbon dioxide.

Key Points

  • Carbon dioxide (CO2) is primarily produced during the burning of coke because coke is primarily composed of carbon.
  • When coke burns in the presence of oxygen, it undergoes a chemical reaction known as combustion, which releases carbon dioxide and energy.
  • The chemical reaction for the combustion of coke is: C + O2 → CO2.
  • This process is widely used in industrial applications, such as in steel manufacturing, where coke serves as a reducing agent in the extraction of iron from its ore.
  • Carbon dioxide is a significant greenhouse gas, and its release into the atmosphere contributes to global warming and climate change.
  • Coke is derived from coal and primarily consists of carbon with minimal impurities, making it efficient for high-temperature processes.
  • The burning of coke is also associated with energy production due to the exothermic nature of the combustion reaction.

 Additional Information

  • Nitrogen dioxide
  • Nitrogen dioxide (NO2) is a toxic gas that is produced during the combustion of fossil fuels, but it is not a major product of coke burning.
  • It is commonly associated with vehicle emissions and industrial processes.
  • NO2 contributes to air pollution and forms part of the group of gases known as nitrogen oxides (NOx).
  • It plays a role in the formation of acid rain and photochemical smog.
  • Oxygen
  • Oxygen (O2) is not a product of coke burning but rather a reactant that is essential for the combustion process.
  • It is a vital element for all combustion reactions and is present in the atmosphere.
  • Oxygen supports the burning of fuels, including coke, by facilitating the release of energy through oxidation.
  • Sulphur dioxide
  • Sulphur dioxide (SO2) is produced when fuels containing sulphur are burned, but coke typically has a low sulphur content.
  • SO2 contributes to acid rain and can harm the environment and human health.
  • It is primarily emitted from the combustion of sulphur-rich coal and oil.

Question 7

Asexual reproduction does NOT involve the formation of ______.

  1. AOption (a)

    buds

  2. BOption (b)

    zygotes

  3. COption (c)

    spores

  4. DOption (d)

    leaves

View answer & explanation

Correct answer

Answer: (b)B.

zygotes

Why this answer is correct

The Correct answer is zygotes.

Key Points

  • Asexual reproduction does not involve the formation of zygotes, as it is a process that occurs without the fusion of gametes.
  • In asexual reproduction, a single parent reproduces offspring that are genetically identical, as there is no mixing of genetic material.
  • Zygote formation is characteristic of sexual reproduction, where male and female gametes fuse to form a diploid cell.
  • Examples of organisms that reproduce asexually include amoeba, bacteria, hydra, and certain plants like bryophytes.
  • Methods of asexual reproduction include budding, binary fission, fragmentation, spore formation, and vegetative propagation.
  • Asexual reproduction is advantageous as it enables rapid reproduction in stable environments and ensures the perpetuation of successful genetic traits.

 Additional Information

  • Buds
  • Budding is a type of asexual reproduction where a new organism develops from an outgrowth or bud due to cell division at one particular site.
  • Examples include hydra and yeast, where the bud eventually detaches to become an independent organism.
  • Spore
  • Spore formation is another mode of asexual reproduction, commonly seen in fungi, algae, and some non-flowering plants like mosses and ferns.
  • It involves the production of spores, which are reproductive units capable of developing into a new organism under favorable conditions.
  • Leaves
  • In certain plants, asexual reproduction can occur through vegetative propagation, where new plants grow from leaves.
  • For instance, the plant Bryophyllum reproduces asexually when plantlets grow along the edges of its leaves.

Question 8

Select the set in which the numbers are related in the same way as are the numbers of the following sets.

(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 --Operations on 13 such as adding/subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

(6, 12, 48)

(8, 16, 64)

  1. AOption (a)

    (15, 30, 130)

  2. BOption (b)

    (15, 40, 120)

  3. COption (c)

    (5, 30, 120)

  4. DOption (d)

    (15, 30, 120)

View answer & explanation

Correct answer

Answer: (d)D.

(15, 30, 120)

Why this answer is correct

The logic followed here is:

Given:

(6, 12, 48)

6 × 6 + 12 = 48

36 + 12 = 48

48 = 48 (LHS = RHS)

And,

(8, 16, 64)

8 × 6 + 16 = 64

48 + 16 = 64

64 = 64 (LHS = RHS)

So, checking each option one by one:

Option 1) (15, 30, 130)

15 × 6 + 30 = 130

90 + 30 = 130

120 ≠ 130 (LHS ≠ RHS)

Option 2) (15, 40, 120)

15 × 6 + 40 = 120

90 + 40 = 120

130 ≠ 120 (LHS ≠ RHS)

Option 3) (5, 30, 120)

5 × 6 + 30 = 120

30 + 30 = 120

60 ≠ 120 (LHS ≠ RHS)

Option 4) (15, 30, 120)

15 × 6 + 30 = 120

90 + 30 = 120

120 = 120 (LHS = RHS)

Thus, out of all the options, '(15, 30, 120)' follows the same logic as given.

Hence, "Option 4" is the correct answer.

Question 9

If a + b + c = 9 and ab + bc + ca = 23, then a2 + b2 + c2 = ?

  1. AOption (a)

    25

  2. BOption (b)

    35

  3. COption (c)

    58

  4. DOption (d)

    127

View answer & explanation

Correct answer

Answer: (b)B.

35

Why this answer is correct

Shortcut Trick

Direct formula application: (a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca).

Substitute the given values: 92 = a2 + b2 + c2 + 2 × 23.

⇒ 81 = a2 + b2 + c2 + 46.

⇒ a2 + b2 + c2 = 81 − 46 = 35.

∴ The correct answer is 35.

Alternate Method

Given:

a + b + c = 9

ab + bc + ca = 23

Formula Used:

(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca

Calculations:

⇒ (a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca)

⇒ (9)2 = a2 + b2 + c2 + 2(23)

⇒ 81 = a2 + b2 + c2 + 46

⇒ a2 + b2 + c2 = 81 − 46

⇒ a2 + b2 + c2 = 35

∴ The correct answer is 35.

Additional Information

Algebraic Identity: Cubic Expansion

a3 + b3 + c3 − 3abc = (a + b + c)(a2 + b2 + c2 − ab − bc − ca).

Special Case: Sum of Squares

If a + b + c = 0, then a3 + b3 + c3 = 3abc.

Alternative Square Form

a2 + b2 + c2 − ab − bc − ca = 1/2 [(a − b)2 + (b − c)2 + (c − a)2].

Question 10

If a stone is thrown up, the value of acceleration due to gravity ‘g’ will be taken as _______.

  1. AOption (a)

    infinite 

  2. BOption (b)

    negative 

  3. COption (c)

    Zero 

  4. DOption (d)

    positive  

View answer & explanation

Correct answer

Answer: (b)B.

negative 

Why this answer is correct

The Correct answer is Negative.

Key Points

  • When a stone is thrown upward, the direction of motion is opposite to the direction of gravitational force.
  • The acceleration due to gravity (g) always acts in the downward direction, i.e., towards the center of the Earth.
  • In this scenario, since the upward motion of the stone is opposite to the direction of gravity, the value of g becomes negative.
  • The negative sign indicates the opposing direction of the gravitational force relative to the motion of the object.
  • As the stone rises, its velocity decreases due to the negative acceleration until it reaches the highest point, where the velocity becomes zero.
  • Once the stone starts to fall back down, the acceleration due to gravity acts in the same direction as its motion, and the value of g becomes positive.
  • This principle is based on the laws of motion and Newton’s universal law of gravitation.
  • Understanding the sign convention of g is crucial for solving various problems in physics, such as projectile motion, free fall, and other kinematic calculations.

 Additional Information

  • Infinite
  • The term infinite is not applicable in this context as the acceleration due to gravity (g) has a fixed value near the Earth's surface, approximately 9.8 m/s².
  • Infinity generally refers to an unbounded or limitless value, which does not describe gravitational acceleration.
  • Zero
  • The value of g cannot be zero as long as the object is within the influence of Earth's gravity.
  • Zero gravitational acceleration would only occur in deep space, far away from any massive object exerting a gravitational pull.
  • Positive
  • The value of g is considered positive when the motion of the object is in the same direction as the gravitational force.
  • In this case, when the stone is falling back down, the acceleration due to gravity becomes positive.

Question 11

Based on the English alphabetical order, three of the following four letter-cluster pairs are alike in a certain way and thus form a group. Which pair does not belong to that group?

(Note: The odd one out is not based on the number of consonants/vowels or their position in the letter-cluster.)

  1. AOption (a)

    TZ—YC 

  2. BOption (b)

    BH-GK 

  3. COption (c)

    WC -BF 

  4. DOption (d)

    AD-YW 

View answer & explanation

Correct answer

Answer: (d)D.

AD-YW 

Why this answer is correct

The logic followed here is:

Option 1) TZ—YC

Option 2) BH-GK

Option 3) WC -BF

Option 4) AD-YW

Thus, out of all the options 'AD-YW' is the odd one out.

Hence, "Option 4" is the correct answer.

Question 12

Which of the following has two ends: one which is hydrophilic and the other which is hydrophobic? 

  1. AOption (a)

    Water 

  2. BOption (b)

    Perfume 

  3. COption (c)

    Cream 

  4. DOption (d)

    Soap 

View answer & explanation

Correct answer

Answer: (d)D.

Soap 

Why this answer is correct

The Correct answer is Soap.

Key Points

  • Soap is a substance that has a dual nature - a hydrophilic (water-attracting) end and a hydrophobic (water-repelling) end.
  • The hydrophilic end of soap is attracted to water molecules, making it soluble in water.
  • The hydrophobic end is attracted to oil, grease, and dirt, helping to remove these substances from surfaces.
  • When soap is mixed with water, it forms structures called micelles, where the hydrophobic ends trap grease and dirt, while the hydrophilic ends remain in water, helping to wash away impurities.
  • Soap is widely used in cleaning, personal hygiene, and industrial processes due to its amphiphilic properties.
  • Soap is made through a process called saponification, where fats or oils are reacted with an alkali, such as sodium hydroxide or potassium hydroxide.
  • Examples of soap products include bar soap, liquid soap, and detergent powders.

 Additional Information

  • Water
  • Water is a universal solvent but does not have amphiphilic properties like soap.
  • It is composed of hydrogen and oxygen (H₂O) and forms hydrogen bonds with other water molecules.
  • It is essential for life and is used in drinking, agriculture, industry, and sanitation.
  • Perfume
  • Perfume is a mixture of fragrant essential oils or aroma compounds, solvents, and fixatives used to create a pleasant smell.
  • It does not have hydrophilic or hydrophobic ends and is insoluble in water.
  • Perfumes are primarily used in personal care products and for aromatherapy.
  • Cream
  • Cream is an emulsion of water and fat and is used in cosmetics, skincare, and food products.
  • While it contains both water and oil, it does not exhibit the dual hydrophilic and hydrophobic properties of soap.
  • Cream products are used for hydration, moisturization, and cooking.

Question 13

Select the triad which follows the same pattern as that followed by the two triads given below. Both triads follow the same pattern.

HE-JG-LN

MJ-OL-QS

  1. AOption (a)

    RO-TQ-VW 

  2. BOption (b)

    QN-SP-UW 

  3. COption (c)

    PM-RO-TU 

  4. DOption (d)

    OL-QN-ST 

View answer & explanation

Correct answer

Answer: (b)B.

QN-SP-UW 

Why this answer is correct

The logic followed here is:

Given: 

HE-JG-LN

And,

MJ-OL-QS 

So, checking each option one by one:

Option 1) RO-TQ-VW

Option 2) QN-SP-UW 

Option 3) PM-RO-TU

Option 4) OL-QN-ST

Thus, out of all the options 'QN-SP-UW ' follows the same logic as given.

Hence, "Option 2" is the correct answer.

Question 14

Which of the following correctly represents the relationship between u(object distance), v (image distance) and f (focal length) of a spherical mirror? 

  1. AOption (a)

    1v+1u=1f\rm \frac{1}{v}+\frac{1}{u}=\frac{1}{f}

  2. BOption (b)

    1v−1u=12f\rm \frac{1}{v}-\frac{1}{u}=\frac{1}{2f}

  3. COption (c)

    1v+1u=12f\rm \frac{1}{v}+\frac{1}{u}=\frac{1}{2f}

  4. DOption (d)

    1v−1u=1f\rm \frac{1}{v}-\frac{1}{u}=\frac{1}{f}

View answer & explanation

Correct answer

Answer: (a)A.

1v+1u=1f\rm \frac{1}{v}+\frac{1}{u}=\frac{1}{f}

Why this answer is correct

The Correct answer is (1/v) + (1/u) = (1/f).

Key Points

  • This equation is known as the Mirror Formula, which establishes a relationship between the object distance (u), image distance (v), and focal length (f) for a spherical mirror.
  • The formula is applicable for both concave and convex mirrors.
  • In the equation, all distances are measured from the pole of the mirror, and the sign convention must be followed to determine the nature of the distances (positive or negative).
  • Concave mirrors form real and inverted images for objects placed beyond the focal point and virtual images when the object is within the focal length.
  • Convex mirrors, however, always produce virtual, erect, and diminished images regardless of the object’s position.
  • The formula is derived from the geometry of the mirror and is used in various applications, including optics, imaging systems, and physics experiments.
  • The equation ensures the quantitative analysis of image formation, allowing scientists and engineers to calculate the exact position and size of the image.

Question 15

Given below is a cause followed by possible effects numbered I, II and III. Read the cause carefully and decide which of the three can be a/the possible effect(s).

Cause:

Heavy rains and flash floods have inundated many low lying areas of City X.

Effects:

(I) The State Government has appointed a new head for the municipality of City X.

(II) The State Government has evacuated over 5500 people stranded in low lying areas of City X.

(III) Food and water is being distributed at multiple locations to help citizens who have been evacuated from City X.

  1. AOption (a)

    Both II and III can be the possible effects

  2. BOption (b)

    Only I can be a possible effect

  3. COption (c)

    Only II can be a possible effect

  4. DOption (d)

    Both I and II can be the possible effects

View answer & explanation

Correct answer

Answer: (a)A.

Both II and III can be the possible effects

Why this answer is correct

Given cause: Heavy rains and flash floods have inundated many low lying areas of City X.

Given effects:

(I) The State Government has appointed a new head for the municipality of City X. → Not possible

As mismanagement during the flood could lead to a leadership change but this is not an immediate or guaranteed effect of the disaster itself. 

(II) The State Government has evacuated over 5500 people stranded in low lying areas of City X. → Possible

When floods occur, authorities often evacuate people from affected areas for safety. The given cause mentions that low lying areas were inundated, making evacuation necessary.

(III) Food and water is being distributed at multiple locations to help citizens who have been evacuated from City X. → Possible

After being displaced, people require basic necessities such as food and water. Disaster relief efforts typically involve such measures, making this a possible and reasonable effect.

Thus, Both II and III can be the possible effects.

Hence, "Option 1" is the correct answer.

Question 16

Which of the following shows Tyndall effect?

  1. AOption (a)

    Solutions

  2. BOption (b)

    Colloids

  3. COption (c)

    Metals

  4. DOption (d)

    Gases

View answer & explanation

Correct answer

Answer: (b)B.

Colloids

Why this answer is correct

The Correct answer is Colloids.

Key Points

  • The Tyndall effect refers to the scattering of light by particles in a medium, making the path of light visible.
  • Colloids are mixtures where the particle size ranges between 1 nm to 1000 nm, large enough to scatter light.
  • When a beam of light passes through a colloidal solution, the light is scattered, and this phenomenon is called the Tyndall effect.
  • Examples of colloids include fog, milk, smoke, and gelatin solutions.
  • The particles in a colloid are dispersed in a continuous medium and are not visible to the naked eye, but their effect on light is noticeable.
  • The visibility of the light beam in colloids demonstrates the presence of dispersed particles, proving the heterogeneous nature of colloids.

 Additional Information

  • Solutions
  • Solutions are homogeneous mixtures where the particle size is smaller than 1 nm.
  • Due to their small particle size, they do not scatter light and hence do not show the Tyndall effect.
  • Examples of solutions include sugar water, salt water, and vinegar.
  • Metals
  • Metals are solid substances with a characteristic luster and high electrical and thermal conductivity.
  • They are not mixtures or dispersions and do not exhibit the Tyndall effect.
  • Examples of metals include iron, gold, silver, and copper.
  • Gases
  • Gases are composed of particles that are widely spaced and move freely.
  • Pure gases do not exhibit the Tyndall effect as their particles are too small to scatter light significantly.
  • Examples of gases include oxygen, nitrogen, and carbon dioxide.

Question 17

A spherical mirror, whose reflecting surface faces towards the centre of the sphere, is called a _______.

  1. AOption (a)

    plano-convex mirror

  2. BOption (b)

    concave mirror

  3. COption (c)

    plane mirror

  4. DOption (d)

    convex mirror

View answer & explanation

Correct answer

Answer: (b)B.

concave mirror

Why this answer is correct

The Correct answer is Concave Mirror.

Key Points

  • A concave mirror is a spherical mirror whose reflecting surface faces towards the centre of the sphere.
  • It is also known as a converging mirror because it reflects light inward toward a focal point.
  • The principal applications of concave mirrors include their use in telescopes, headlights, shaving mirrors, and dental mirrors, where a magnified image is required.
  • Concave mirrors are capable of forming both real and virtual images depending on the position of the object.
  • The focal length of a concave mirror is half the radius of curvature, denoted mathematically as f = R/2.
  • They are widely used in scientific instruments due to their ability to focus light accurately.
  • Concave mirrors are also used in solar concentrators to focus sunlight for generating heat or energy.

 Additional Information

  • Plano-convex Mirror
  • Plano-convex mirrors have a flat surface on one side and a convex surface on the other.
  • They are not spherical mirrors but are typically used in optical systems for focusing or collimating light.
  • These mirrors are mainly used in lasers, imaging systems, and optical instruments.
  • Plane Mirror
  • A plane mirror has a flat reflecting surface.
  • It reflects light to form a virtual image that is upright and of the same size as the object.
  • Plane mirrors are commonly used in bathrooms, dressing tables, and optical setups.
  • They do not have the capability to converge or diverge light.
  • Convex Mirror
  • A convex mirror is a spherical mirror whose reflecting surface bulges outward.
  • It is also known as a diverging mirror because it spreads light outward.
  • Convex mirrors always form a virtual, upright, and diminished image.
  • They are widely used in vehicle rearview mirrors, surveillance systems, and blind spot detection.

Question 18

In September 2024, L&T Semiconductor Technologies (SiLT) signed an agreement with which of the following companies to co-develop advanced processors for edge devices, hybrid cloud systems and areas like mobility, industrial, energy and servers? 

  1. AOption (a)

    Nvidia

  2. BOption (b)

    Intel

  3. COption (c)

    Dell

  4. DOption (d)

    IBM

View answer & explanation

Correct answer

Answer: (d)D.

IBM

Why this answer is correct

The Correct answer is IBM.

Key Points

  • L&T Semiconductor Technologies (SiLT) signed a partnership agreement with IBM in September 2024.
  • This collaboration aims to co-develop advanced processors for edge devices, hybrid cloud systems, and areas like mobility, industrial, energy, and servers.
  • IBM is a globally renowned technology company that specializes in hardware, software, and cutting-edge technology solutions, such as AI, cloud computing, and quantum computing.
  • The focus of the partnership is to leverage IBM's expertise in processor development and SiLT's capabilities in semiconductor technology to address the growing demand for innovative solutions in these sectors.
  • This collaboration is expected to foster technological advancements and boost India's semiconductor industry, aligning with the country's ambition to become a global hub for semiconductor manufacturing.
  • Edge devices are critical components in modern computing systems, enabling real-time data processing closer to the source, thereby reducing latency and improving efficiency.

 Additional Information

  • Nvidia
  • Nvidia is a leading company in graphics processing units (GPUs) and AI hardware.
  • Nvidia is known for its contributions to gaming technology and its role in advancing AI development through platforms like CUDA.
  • Although Nvidia is a key player in the technology sector, it is not directly involved in this specific collaboration with L&T Semiconductor Technologies.
  • Intel
  • Intel is one of the largest semiconductor chip manufacturers globally, known for its processors and innovations in computing technology.
  • Intel specializes in developing processors for personal computers, servers, and mobile devices.
  • While Intel plays a significant role in the semiconductor industry, it is not the company collaborating with SiLT in this case.
  • Dell
  • Dell is a multinational computer technology company known for its hardware solutions like laptops, desktops, and servers.
  • Although Dell is a major player in the technology industry, its expertise lies more in hardware manufacturing rather than semiconductor or processor development.

Question 19

Which of the following statements about a colloidal solution is INCORRECT? 

  1. AOption (a)

    Colloidal solutions are a heterogeneous mixture. 

  2. BOption (b)

    Components cannot be separated by the process of filtration.  

  3. COption (c)

    Fog is an example of a colloidal solution. 

  4. DOption (d)

    Milk is not a colloidal solution. 

View answer & explanation

Correct answer

Answer: (d)D.

Milk is not a colloidal solution. 

Why this answer is correct

The Correct answer is Milk is not a colloidal solution.

Key Points

  • Milk is, in fact, a colloidal solution, not a non-colloidal solution as mentioned in the question.
  • A colloidal solution is a heterogeneous mixture where one substance is dispersed evenly throughout another.
  • In milk, fat globules are dispersed in water, making it an example of an emulsion, which is a type of colloidal solution.
  • The particles in colloidal solutions, such as milk, are so small that they do not settle down and cannot be separated by ordinary filtration methods.
  • Milk exhibits the Tyndall effect, which is a characteristic property of colloids, where light is scattered by the dispersed particles.
  • Examples of colloidal solutions like milk are common in daily life and include substances such as fog, whipped cream, and jelly.

 Additional Information

  • Colloidal solutions are a heterogeneous mixture
  • A heterogeneous mixture is one where the composition is not uniform throughout the solution.
  • In a colloidal solution, the dispersed phase (small particles) and the dispersion medium (substance in which particles are dispersed) remain separate, making it heterogeneous.
  • Examples of colloidal solutions include fog, smoke, and milk.
  • Components cannot be separated by the process of filtration
  • The particles in a colloidal solution are very small, typically in the range of 1-1000 nanometers.
  • Due to their small size, they pass through ordinary filter paper, and hence, filtration cannot separate them.
  • Specialized methods like ultrafiltration are required to separate colloidal particles.
  • Fog is an example of a colloidal solution
  • Fog is an example of an aerosol, which is a type of colloidal solution where tiny liquid droplets are dispersed in air.
  • The particles in fog scatter light, making it another example of the Tyndall effect.
  • This dispersion of water droplets in air is why fog reduces visibility significantly.

Question 20

In a certain code language, ‘POEM’ is coded as ‘7591' and ‘MINT’ is coded as '6728'. What is the code for ‘M’ in the given code language?  

  1. AOption (a)

    7

  2. BOption (b)

    1

  3. COption (c)

    6

  4. DOption (d)

    2

View answer & explanation

Correct answer

Answer: (a)A.

7

Why this answer is correct

The logic followed here is:

‘POEM’ is coded as ‘7591'

‘MINT’ is coded as '6728'

Thus, code for ‘M’ is '7'.

Hence, "Option 1" is the correct answer.

Question 21

Find the area of a rhombus whose side is 25 cm and one of the diagonals is 30 cm?  

  1. AOption (a)

    360 sq cm

  2. BOption (b)

    225 sq cm 

  3. COption (c)

    600 sq cm

  4. DOption (d)

    720 sq cm

View answer & explanation

Correct answer

Answer: (c)C.

600 sq cm

Why this answer is correct

Shortcut Trick

In a rhombus, diagonals bisect each other at 90°. Half of the given diagonal is 15 cm.

Using the Pythagorean triplet (15, 20, 25), where 25 is the hypotenuse (side of rhombus), the other half-diagonal must be 20 cm.

Full length of the second diagonal d2 = 20 × 2 = 40 cm.

Area = (1/2) × d1 × d2 = (1/2) × 30 × 40 = 600 cm2.

∴ The correct answer is 600 sq cm.

Alternate Method

Given: Side (a) = 25 cm, Diagonal 1 (d1) = 30 cm.

Formula Used: 4 × a2 = d12 + d22 and Area = (1/2) × d1 × d2.

⇒ 4 × (25)2 = (30)2 + d22

⇒ 4 × 625 = 900 + d22

⇒ 2500 − 900 = d22

⇒ d22 = 1600

⇒ d2 = 40 cm

⇒ Area = (1/2) × 30 × 40 = 600 cm2

∴ The correct answer is 600 sq cm.

Additional Information

Properties of a Rhombus

All sides are equal and opposite angles are equal. Diagonals bisect each other at right angles (90°).

Perimeter of Rhombus

The perimeter is given by the formula P = 4 × side.

Relation between Side and Diagonals

Side (a) = (1/2) √(d12 + d22).

Question 22

Where is glucose converted into pyruvate? 

  1. AOption (a)

    Ribosome 

  2. BOption (b)

    Cytoplasm 

  3. COption (c)

    Golgi-complex  

  4. DOption (d)

    Mitochondria 

View answer & explanation

Correct answer

Answer: (b)B.

Cytoplasm 

Why this answer is correct

The Correct answer is Cytoplasm.

Key Points

  • Glucose is converted into pyruvate through a process known as glycolysis.
  • Glycolysis is an anaerobic process, meaning it does not require oxygen to occur.
  • This process occurs in the cytoplasm of the cell, which is the gel-like substance that surrounds the cell organelles.
  • During glycolysis, one molecule of glucose (6-carbon molecule) is broken down into two molecules of pyruvate (3-carbon molecule).
  • This process generates a small amount of energy in the form of ATP (Adenosine Triphosphate) and NADH (Nicotinamide Adenine Dinucleotide).
  • The pyruvate produced in the cytoplasm can then enter the mitochondria for further energy production through processes such as the Krebs cycle and oxidative phosphorylation, if oxygen is available.
  • Glycolysis is the first step of cellular respiration and is essential for energy production in both prokaryotic and eukaryotic organisms.

 Additional Information

  • Ribosome
  • The ribosome is the site of protein synthesis in the cell.
  • It is not involved in the process of glycolysis or the conversion of glucose into pyruvate.
  • Ribosomes are found either floating freely in the cytoplasm or attached to the endoplasmic reticulum.
  • Golgi-complex
  • The Golgi apparatus, also known as the Golgi-complex, is responsible for modifying, sorting, and packaging proteins and lipids for secretion or use within the cell.
  • It has no role in the metabolic pathway of glycolysis.
  • Mitochondria
  • The mitochondria are known as the powerhouse of the cell and are the site of aerobic respiration.
  • The pyruvate generated in the cytoplasm during glycolysis is transported to the mitochondria for further breakdown in the Krebs cycle and electron transport chain to produce a larger amount of ATP.
  • However, glycolysis itself does not occur in the mitochondria.

Question 23

Divit starts from point A and drives 4 km towards the East. He then takes two simultaneous right turns and drives 2 km and 4 km, respectively. He takes another right turn and drives 5 km. He then takes a left turn and drives 3 km. He takes a final left turn and drives 3 km to reach point B. How far (shortest distance) and towards which direction should he drive to reach Point A again? (All turns are 90 degrees turns only unless specified.)

  1. AOption (a)

    3 km north

  2. BOption (b)

    3 km South

  3. COption (c)

    3 km East

  4. DOption (d)

    3 km West

View answer & explanation

Correct answer

Answer: (c)C.

3 km East

Why this answer is correct

Given:

Divit starts from point A and drives 4 km towards the East.

He then takes two simultaneous right turns and drives 2 km and 4 km, respectively.

He takes another right turn and drives 5 km.

He then takes a left turn and drives 3 km.

He takes a final left turn and drives 3 km to reach point B.

Thus, Divit should drive (5 km - 2 km) 3 km in the east direction in order to reach Point A again.

Hence, "Option 3" is the correct answer.

Question 24

The effective resistance of the parallel combination of two resistors is always _______

  1. AOption (a)

    less than the resistance of the individual resistors

  2. BOption (b)

    equal to the product of resistance of the individual resistors 

  3. COption (c)

    greater than the resistance of the individual resistors

  4. DOption (d)

    equal to the sum of the resistance of the resistors

View answer & explanation

Correct answer

Answer: (a)A.

less than the resistance of the individual resistors

Why this answer is correct

The Correct answer is less than the resistance of the individual resistors.

Key Points

  • The effective resistance of a parallel combination of resistors is always less than the resistance of the smallest individual resistor in the circuit.
  • In a parallel circuit, the total current through the circuit is the sum of the currents through each resistor.
  • As more paths are provided for the current to flow, the overall resistance decreases.
  • The formula to calculate the effective resistance for two resistors connected in parallel is:

1/Reffective = 1/R1 + 1/R2.

  • This relationship ensures that the effective resistance is always less than any of the individual resistances.
  • For example, if two resistors with resistances of 10 Ω and 20 Ω are connected in parallel, the effective resistance will be around 6.67 Ω, which is less than both 10 Ω and 20 Ω.
  • Parallel resistors are commonly used in circuits to reduce resistance and allow more current to flow.

Question 25

If a current of 1 A is flowing through a conductor for 10 secs, then the charge flowing through it (in coulombs) will be:

  1. AOption (a)

    1

  2. BOption (b)

    0.1

  3. COption (c)

    10

  4. DOption (d)

    100

View answer & explanation

Correct answer

Answer: (c)C.

10

Why this answer is correct

The Correct answer is 10 Coulombs.

Key Points

  • The relationship between current (I), charge (Q), and time (t) is given by the formula: I = Q / t.
  • Rearranging the formula to calculate charge, we get: Q = I × t.
  • Here, the current (I) is 1 A (ampere) and the time (t) is 10 seconds.
  • Substituting the values into the formula: Q = 1 × 10 = 10 Coulombs.
  • Charge is measured in the unit of coulombs, which represents the quantity of electricity transported.
  • This means that a current of 1 ampere flowing for 10 seconds results in a total charge flow of 10 coulombs.
  • This calculation is based on the fundamental relationship in electricity and magnetism, forming the basis for understanding current flow in circuits.

 Additional Information

  • Concept of Current:
  • Current (I) is the rate at which charge flows through a conductor.
  • It is measured in amperes (A), where 1 ampere represents the flow of 1 coulomb of charge per second.
  • Charge (Q):
  • Charge is a fundamental property of matter associated with the presence of electrons or protons.
  • It is measured in coulombs (C).
  • The charge of a single electron is approximately -1.6 × 10⁻¹⁹ coulombs.
  • Practical Application of Formula:
  • This formula is used in various fields such as electronics, electrical engineering, and physics to calculate the flow of charge in circuits.
  • It helps in determining the amount of energy transferred in a circuit over a given time.

Question 26

The value of acceleration due to gravity 'g' is _______ 

  1. AOption (a)

    negative at the equator and positive at the poles

  2. BOption (b)

    greater at the equator than at the poles

  3. COption (c)

    the same at the poles and equator

  4. DOption (d)

    greater at the poles than at the equator

View answer & explanation

Correct answer

Answer: (d)D.

greater at the poles than at the equator

Why this answer is correct

The correct answer is greater at the poles than at the equator.

Key Points

  • The acceleration due to gravity (g) is not uniform across the Earth's surface due to its non-spherical shape and rotational motion.
  • The Earth is an oblate spheroid, meaning it is flattened at the poles and bulges at the equator.
  • At the poles, the distance between the Earth's center and the surface is shorter compared to the equator. Since gravity is inversely proportional to the square of the distance, g is greater at the poles.
  • The Earth's rotational motion creates a centrifugal force, which is maximum at the equator and reduces the net gravitational pull. This centrifugal force is negligible at the poles, resulting in a higher value of g.
  • Mathematically, the relationship between gravity and distance can be expressed as g ∝ 1/r², where r is the radius of the Earth at a given location.
  • Thus, the combination of the Earth's shape and rotation explains why gravity is greater at the poles than at the equator.

Question 27

Which of the following options is the same as Newton’s second law of motion? 

  1. AOption (a)

    Applied force on a body is inversely proportional to the acceleration of the body. 

  2. BOption (b)

    The rate of change of momentum of an object is independent of the applied unbalanced force.  

  3. COption (c)

    An object at rest will remain at rest when external force is not applied. 

  4. DOption (d)

    If an object is in motion, applied force is directly proportional to the acceleration. 

View answer & explanation

Correct answer

Answer: (d)D.

If an object is in motion, applied force is directly proportional to the acceleration. 

Why this answer is correct

The Correct answer is If an object is in motion, applied force is directly proportional to the acceleration.

Key Points

  • Newton's second law of motion states that the force applied to an object is directly proportional to the rate of change of momentum, and for a constant mass, it is directly proportional to the acceleration of the object. Mathematically, it is expressed as: F = ma, where F is the force, m is the mass, and a is the acceleration.
  • It explains the relationship between the force applied on an object, its mass, and the resulting acceleration. This law is fundamental in understanding motion in physics.
  • The second law is crucial for calculating forces in various applications such as engineering, mechanics, and aerospace sciences.
  • This principle is applied in real-life scenarios like vehicle acceleration, the motion of projectiles, and the study of gravitational forces.
  • It helps determine how much force is required to move or stop an object, which is important in designing machines and ensuring safety measures.

Question 28

Express the speed of 36 km/h in m/s. 

  1. AOption (a)

    78 m/s 

  2. BOption (b)

    10 m/s 

  3. COption (c)

    60 m/s  

  4. DOption (d)

    11 m/s 

View answer & explanation

Correct answer

Answer: (b)B.

10 m/s 

Why this answer is correct

Shortcut Trick

To convert km/h to m/s, multiply the speed by the fraction 5/18.

Speed in m/s = 36 × (5/18)

Speed in m/s = 2 × 5 = 10 m/s

∴ The correct answer is 10 m/s.

Alternate Method

Given: Speed = 36 km/h

Formula Used: 1 km = 1000 m and 1 hour = 3600 seconds

⇒ Speed = 36 × (1000 m / 3600 s)

⇒ Speed = 36 × (10 / 36) m/s

⇒ Speed = 1 × 10 m/s

⇒ Speed = 10 m/s

∴ The correct answer is 10 m/s.

Additional Information

Unit Conversion Factor

To convert m/s back to km/h, multiply by the reciprocal 18/5.

Average Speed

Average Speed = Total Distance ÷ Total Time. For two equal distances at speeds a and b, Average Speed = 2ab/(a+b).

Relative Speed

In the same direction, subtract speeds (S1 − S2). In opposite directions, add speeds (S1 + S2).

Question 29

Which of the given statements is/are correct?

a) There are two types of waste: biodegradable and non-biodegradable.

b) We should collect dry waste and wet waste separately.

  1. AOption (a)

    Neither a) nor b) 

  2. BOption (b)

    Only b) 

  3. COption (c)

    Both a) and b) 

  4. DOption (d)

    Only a)  

View answer & explanation

Correct answer

Answer: (c)C.

Both a) and b) 

Why this answer is correct

The Correct answer is Both a) and b).

Key Points

  • Waste can be classified into two main categories: biodegradable and non-biodegradable.
  • Biodegradable waste includes organic materials like food scraps, paper, and plant debris that decompose naturally.
  • Non-biodegradable waste includes plastics, metals, and glass that do not decompose easily and may harm the environment.
  • It is essential to separate dry waste (like plastics, metals, glass) and wet waste (organic waste) for proper disposal and recycling.
  • Segregation of waste aids in the efficient recycling process and minimizes environmental hazards.
  • Biodegradable waste can be turned into compost, which is beneficial for agriculture, while non-biodegradable waste can be recycled to reduce pollution.
  • Proper waste segregation practices align with global efforts to promote sustainable waste management.

Question 30

A tank was filled with 300 ltr of water. During the day 87 ltr 225 ml of water was used. How much water was left in the tank at the end of the day?

  1. AOption (a)

    212 ltr 775 ml

  2. BOption (b)

    212 ltr 675 ml

  3. COption (c)

    212 ltr 875ml

  4. DOption (d)

    212 ltr 825ml

View answer & explanation

Correct answer

Answer: (a)A.

212 ltr 775 ml

Why this answer is correct

Shortcut Trick

Subtract the milliliters first by borrowing 1 ltr (1000 ml) from the total capacity.

1000 ml − 225 ml = 775 ml

299 ltr − 87 ltr = 212 ltr

Result: 212 ltr 775 ml

∴ The correct answer is 212 ltr 775 ml.

Alternate Method

Given:

Initial quantity of water in tank = 300 ltr

Quantity of water used = 87 ltr 225 ml

Formula Used:

Water left = Total water − Used water

1 liter = 1000 milliliters

Calculations:

⇒ Total water = 300.000 ltr

⇒ Used water = 87.225 ltr

⇒ Water left = 300.000 − 87.225

⇒ Water left = 212.775 ltr

⇒ 212.775 ltr = 212 ltr 775 ml

∴ The correct answer is 212 ltr 775 ml.

Additional Information

Metric Conversion

Standard unit of volume is liters. 1 Liter (L) = 1000 Milliliters (ml). To convert L to ml, multiply by 1000.

Subtraction with Units

When subtracting mixed units, subtract the smaller units first. If the upper value is smaller, borrow 1 unit from the larger category (e.g., borrow 1 ltr to get 1000 ml).

Question 31

Which of the following was not one of the nine priority areas of the Union Budget 2024-25 aimed at generating ample opportunities for all?

  1. AOption (a)

    Employment and Skill Training

  2. BOption (b)

    Energy security

  3. COption (c)

    Manufacturing and Services

  4. DOption (d)

    Sustainable development of fisheries

View answer & explanation

Correct answer

Answer: (d)D.

Sustainable development of fisheries

Why this answer is correct

The correct answer is Sustainable development of fisheries.

Key Points

  • The central budget for 2024-25 focused on nine priority areas aimed at creating opportunities for all. These areas were aligned with the government's vision of inclusive growth and economic development.
  • While critical sectors like employment, skills, energy security, and manufacturing and services were emphasized, “Sustainable development of fisheries” was not explicitly mentioned as one of the budget’s highlighted priority areas.
  • The nine priority areas generally focused on infrastructure, digital transformation, green energy, and human capital development, leaving out fisheries as a distinct focus area in this context.
  • However, fisheries and allied sectors may still be part of broader schemes or programs under the government’s agricultural and rural development initiatives.
  • The omission of fisheries as a specific priority does not undermine its importance but reflects a strategic focus on other sectors driving macroeconomic growth.

 Additional Information

  • Employment and Skill Training
  • The budget emphasized employment generation through skill development programs, particularly focusing on youth and women.
  • Programs like PM Kaushal Vikas Yojana and initiatives for skilling in emerging technologies (e.g., AI, IoT) were highlighted.
  • Energy Security
  • Energy security was a prominent priority area in the budget, focusing on renewable energy projects and reducing dependency on fossil fuels.
  • Significant investments were allocated for green hydrogen, solar energy parks, and energy transition initiatives.
  • Manufacturing and Services
  • The budget aimed to boost the manufacturing sector through Production Linked Incentive (PLI) schemes and promote services such as IT, tourism, and finance.
  • This focus was intended to enhance India's global competitiveness and contribute to the goal of Aatmanirbhar Bharat.

Question 32

Who among the following is a Tamil Nadu bus conductor, known for planting 3 lakh saplings over 30 years, has won multiple awards for his eco-activism?

  1. AOption (a)

    Marimuthu Yoganathan

  2. BOption (b)

    MS Swaminathan

  3. COption (c)

    Vijay Kumar

  4. DOption (d)

    Sundar Pichai 

View answer & explanation

Correct answer

Answer: (a)A.

Marimuthu Yoganathan

Why this answer is correct

The Correct answer is Marimuthu Yoganathan.

Key Points

  • Marimuthu Yoganathan is a bus conductor from the state of Tamil Nadu, India, who has dedicated his life to environmental conservation.
  • He is widely recognized for his remarkable achievement of planting over 3 lakh saplings over a span of 30 years.
  • He has been actively involved in eco-activism while simultaneously working as a bus conductor in the Tamil Nadu State Transport Corporation (TNSTC).
  • Marimuthu Yoganathan's efforts have earned him several awards and accolades for his contributions to environmental sustainability.
  • He is also known for educating the public, especially students, about the importance of tree plantation and environmental protection.
  • Despite his modest background, he has made a significant impact by using his personal resources and time for this noble cause.
  • His initiative has inspired many others to take up environmental conservation as a personal responsibility.

 Additional Information

  • MS Swaminathan
  • MS Swaminathan is known as the Father of the Indian Green Revolution.
  • He played a key role in developing and introducing high-yielding varieties (HYVs) of crops in India, leading to increased agricultural productivity.
  • His work primarily focused on food security and sustainable agriculture.
  • Vijay Kumar
  • The name Vijay Kumar does not directly relate to notable environmental or eco-activism contributions in the context of this question.
  • Sundar Pichai
  • Sundar Pichai is the CEO of Alphabet Inc. and Google.
  • He is a well-known figure in the technology and innovation sector, not directly associated with environmental activism.
  • He was born in Chennai, Tamil Nadu, India, and has had a significant impact on global technology advancements.

Question 33

The pressure exerted on a body is 10 Nm-2, if the area of the body is 2 m2 : then the thrust acting on the body will be:

  1. AOption (a)

    2 N

  2. BOption (b)

    20 N

  3. COption (c)

    10 N

  4. DOption (d)

    5 N

View answer & explanation

Correct answer

Answer: (b)B.

20 N

Why this answer is correct

The Correct answer is 20 N.

Key Points

  • Pressure is defined as the force exerted per unit area of a surface.
  • The formula for calculating pressure is Pressure = Force/Area.
  • In this case, the pressure is given as 10 N/m² and the area of the body is 2 m².
  • To find the thrust (or force) acting on the body, we use the formula Thrust = Pressure × Area.
  • Substituting the values into the formula: Thrust = 10 × 2 = 20 N.
  • The thrust acting on the body is therefore 20 N, which corresponds to the correct option.
  • Thrust is a term used to describe the total force exerted perpendicular to a surface.
  • This concept is important in mechanics and fluid dynamics to understand the interaction between forces and surfaces.

 Additional Information

  • Pressure
  • Pressure is measured in units of Newton per square meter (N/m²), also known as Pascals (Pa).
  • It is widely used in areas such as engineering, physics, fluid mechanics, and material science.
  • Pressure is a scalar quantity, meaning it has magnitude but no direction.
  • Thrust
  • Thrust is a term used to describe the perpendicular force exerted by a body on a surface.
  • It is commonly discussed in the context of aerodynamics, fluid dynamics, and propulsion systems.
  • Thrust is measured in units of Newton (N), which is the standard unit for force in the International System of Units (SI).
  • Area
  • Area is a measure of the surface covered by a shape or object.
  • It is expressed in square units such as m² in the SI system.
  • Understanding area is essential for calculations involving pressure, thrust, and energy distribution.

Question 34

What is the filtration unit of the kidney? 

  1. AOption (a)

    Neuron  

  2. BOption (b)

    Seminiferous tubule 

  3. COption (c)

    Sperm 

  4. DOption (d)

    Nephron 

View answer & explanation

Correct answer

Answer: (d)D.

Nephron 

Why this answer is correct

The Correct answer is Nephron.

Key Points

  • The nephron is the basic structural and functional unit of the kidney.
  • It is responsible for the filtration, reabsorption, secretion, and excretion of waste products and excess substances from the blood.
  • Each kidney contains millions of nephrons, which contribute to maintaining the body's fluid and electrolyte balance.
  • The nephron consists of the following parts:
  • Bowman's Capsule: Encapsulates the glomerulus and facilitates filtration.
  • Glomerulus: A cluster of capillaries that filters blood to remove waste.
  • Proximal Convoluted Tubule: Reabsorbs essential nutrients like glucose, amino acids, and ions.
  • Loop of Henle: Concentrates urine by reabsorbing water and salts.
  • Distal Convoluted Tubule: Adjusts the composition of filtrate by secreting ions and reabsorbing water.
  • Collecting Duct: Finalizes urine composition and transports it to the renal pelvis.
  • Nephrons play a critical role in regulating blood pressure through mechanisms like the Renin-Angiotensin-Aldosterone System (RAAS).
  • They also help maintain the body's acid-base balance by excreting hydrogen ions and reabsorbing bicarbonate ions.
  • The health of nephrons is essential for preventing conditions like chronic kidney disease (CKD) and acute kidney injury (AKI).

 Additional Information

  • Neuron
  • A neuron is the basic unit of the nervous system, responsible for transmitting nerve impulses.
  • It consists of three main parts: cell body, dendrites, and axon.
  • Neurons are not involved in filtration processes; their function is in communication between the brain and other parts of the body.
  • Seminiferous tubule
  • Seminiferous tubules are located in the testes and are involved in the production of sperm cells.
  • They are not related to the kidney or filtration functions.
  • Sperm
  • Sperm is the male reproductive cell, produced in the testes.
  • It has no role in kidney filtration or the excretion of waste products.

Question 35

_______ is useful for the survival of species over time. 

  1. AOption (a)

    Reproduction 

  2. BOption (b)

    Budding 

  3. COption (c)

    Population 

  4. DOption (d)

    Variation 

View answer & explanation

Correct answer

Answer: (d)D.

Variation 

Why this answer is correct

The Correct answer is Variation.

Key Points

  • Variation is essential for the survival of species over time as it helps organisms adapt to changing environments.
  • It occurs due to genetic differences among individuals within a species.
  • Variations can arise through processes like mutation, recombination during reproduction, and environmental factors.
  • These differences may provide certain individuals with a survival advantage, especially when environmental conditions change.
  • This mechanism leads to natural selection, which ensures that favorable traits are passed on to future generations.
  • For example, the development of antibiotic resistance in bacteria is an outcome of genetic variation and selection pressure.
  • It contributes to the evolution of species, ensuring long-term survival and adaptability.
  • Without variation, species would be unable to cope with new challenges like diseases, predators, or climate changes, leading to extinction.

 Additional Information

  • Reproduction
  • Reproduction is the biological process by which new individual organisms are produced.
  • It ensures the continuity of species but does not directly aid in the survival of species in changing environments.
  • There are two types of reproduction: sexual reproduction (involving two parents and genetic variation) and asexual reproduction (involving one parent and no variation).
  • Budding
  • Budding is a type of asexual reproduction commonly seen in organisms like yeast and hydra.
  • It involves the formation of a new organism from a small projection or bud on the parent organism.
  • Since it is a type of asexual reproduction, it does not lead to genetic variation.
  • Population
  • A population refers to the group of individuals of the same species living in a particular area.
  • While the size and density of a population are important, they do not directly ensure the survival of species in changing environments.

Question 36

If each vowel in the word DREAMS is changed to the letter following it in the English alphabetical order and each consonant is changed to the letter following it in the English alphabetical order and the set of letters thus arrived are then rearranged in English alphabetical order, then which of the following letters will be fourth from the right in the group of letters thus formed?  

  1. AOption (a)

    S

  2. BOption (b)

    E

  3. COption (c)

    N

  4. DOption (d)

    F

View answer & explanation

Correct answer

Answer: (d)D.

F

Why this answer is correct

Given word: DREAMS

According to the question,

Given wordDREAMS
Vowel → (+1) Consonant → (+1)(+1)(+1)(+1)(+1)(+1)(+1)
ResultantESFBNT
Arranged in English alphabetical orderBEFNST

Thus, the new formed letter cluster → B E F N S T

So, fourth from the right in the group of letters thus formed: (Left end) B E F N S T (Right end) → F

Hence, "Option 4" is the correct answer.

Question 37

Genes that control the characteristics of a trait are located on: 

  1. AOption (a)

    chromosomes 

  2. BOption (b)

    vacuoles 

  3. COption (c)

    endoplasmic reticulum  

  4. DOption (d)

    lysosome 

View answer & explanation

Correct answer

Answer: (a)A.

chromosomes 

Why this answer is correct

The Correct answer is chromosomes.

Key Points

  • Chromosomes are thread-like structures made up of DNA and associated proteins found in the nucleus of most living cells.
  • They carry genetic information in the form of genes, which determine the characteristics of an organism.
  • Each chromosome contains a tightly packed DNA molecule, which is organized into functional units called genes.
  • Genes are responsible for controlling heredity and traits like eye color, height, and certain diseases.
  • In humans, there are 46 chromosomes (23 pairs), with one set inherited from each parent.
  • Chromosomes are visible under a microscope during the cell division process (mitosis and meiosis).
  • The DNA within chromosomes carries instructions for the development, functioning, growth, and reproduction of all living organisms and many viruses.
  • The study of chromosomes and genes is crucial in the field of genetics and has numerous applications in medicine, agriculture, and evolutionary biology.

 Additional Information

  • Vacuoles
  • Vacuoles are membrane-bound organelles found in both plant and animal cells, but they are much larger in plants.
  • In plant cells, vacuoles help in storing water, nutrients, and waste products and play a role in maintaining turgor pressure to provide structural support.
  • In animal cells, vacuoles are smaller and are involved in processes like endocytosis and exocytosis.
  • Endoplasmic Reticulum (ER)
  • The endoplasmic reticulum (ER) is a network of membrane-bound tubules and sacs in the cytoplasm of eukaryotic cells.
  • It is divided into two types: rough ER (studded with ribosomes) and smooth ER (lacking ribosomes).
  • The rough ER is involved in protein synthesis, while the smooth ER plays a role in lipid synthesis, detoxification, and calcium storage.
  • Lysosome
  • Lysosomes are membrane-bound organelles containing digestive enzymes.
  • They are responsible for breaking down cellular waste, damaged organelles, and macromolecules, a process known as autophagy.
  • Lysosomes are often referred to as the "suicidal bags" of the cell because they can digest the cell itself under certain conditions.

Question 38

In surrogacy cases, the surrogate as well as the commissioning mother may be granted maternity leave of how many days, in case either or both of them are government servants, as per new rule passed by the Indian Government in June 2024?

  1. AOption (a)

    180

  2. BOption (b)

    30

  3. COption (c)

    45

  4. DOption (d)

    90

View answer & explanation

Correct answer

Answer: (a)A.

180

Why this answer is correct

The Correct answer is 180 days.

Key Points

  • The Indian Government has introduced a new rule in June 2024, granting maternity leave for both the surrogate mother and the commissioning mother in surrogacy cases.
  • As per this rule, 180 days of maternity leave can now be availed by government employees in these roles.
  • The decision was taken to recognize the physical, emotional, and mental demands of motherhood, irrespective of whether it is through natural birth or surrogacy.
  • This measure ensures gender equality and supports the concept of work-life balance for women in government service.
  • It is a step in alignment with India's commitment to maternal health and the rights of women as highlighted in Sustainable Development Goals (SDGs).
  • The rule acknowledges that both the surrogate and commissioning mothers play crucial roles in the childbirth process, requiring adequate rest and recovery time.
  • The provision applies specifically to government servants, reflecting progressive steps toward inclusive maternity benefits in the workplace.

Question 39

The wickets taken by a bowler in 10 cricket matches are 2, 6, 4, 5, 0, 2, 1, 3, 2, 3. The mode of the data is: 

  1. AOption (a)

    3

  2. BOption (b)

    1

  3. COption (c)

    0

  4. DOption (d)

    2

View answer & explanation

Correct answer

Answer: (d)D.

2

Why this answer is correct

Shortcut Trick

Mode is the value that appears most frequently in a given data set.

By observation, the frequencies of the wickets taken are:

0 → 1 time, 1 → 1 time, 3 → 2 times, 4 → 1 time, 5 → 1 time, 6 → 1 time, and 2 → 3 times.

Since 2 has the highest frequency (occurs 3 times), the mode is 2.

∴ The correct answer is 2.

Alternate Method

Given:

Data set of wickets taken: 2, 6, 4, 5, 0, 2, 1, 3, 2, 3

Formula Used:

Mode = Value with the maximum frequency in the observation set.

Calculations:

Arranging the data in ascending order: 0, 1, 2, 2, 2, 3, 3, 4, 5, 6

⇒ Number of times 0 occurs = 1

⇒ Number of times 1 occurs = 1

⇒ Number of times 2 occurs = 3

⇒ Number of times 3 occurs = 2

⇒ Number of times 4 occurs = 1

⇒ Number of times 5 occurs = 1

⇒ Number of times 6 occurs = 1

⇒ The observation with the highest frequency is 2 with a frequency of 3.

⇒ Mode = 2

∴ The correct answer is 2.

Additional Information

Empirical Relationship

For a moderately skewed distribution, the relationship between mean, median, and mode is given by: Mode = 3 × Median − 2 × Mean.

Bimodal and Multimodal Data

If two or more values share the same maximum frequency, the data set can have more than one mode (bimodal or multimodal).

Question 40

A shopkeeper sells an item for Rs. 571.20 after giving two successive discounts of 20% and 15% on its marked price. What is the marked price (in Rs. ) of the item?  

  1. AOption (a)

    820

  2. BOption (b)

    780

  3. COption (c)

    840

  4. DOption (d)

    760

View answer & explanation

Correct answer

Answer: (c)C.

840

Why this answer is correct

Shortcut Trick

Net Discount % = 20 + 15 − (20 × 15)/100 = 35 − 3 = 32%

Selling Price % = 100% − 32% = 68%

Given: 68% of Marked Price = 571.20

Marked Price = (571.20 ÷ 68) × 100 = 8.4 × 100 = 840

∴ The correct answer is 840.

Alternate Method

Given: Selling Price (SP) = Rs. 571.20, Discount 1 (d1) = 20%, Discount 2 (d2) = 15%

Formula Used: SP = MP × (100 − d1)/100 × (100 − d2)/100

MP (x) −20%

Price 1 −15%

SP = 571.20 MP = 571.20 ÷ (0.80 × 0.85)

⇒ 571.20 = MP × (100 − 20)/100 × (100 − 15)/100

⇒ 571.20 = MP × (80/100) × (85/100)

⇒ 571.20 = MP × (4/5) × (17/20)

⇒ 571.20 = MP × (68/100)

⇒ MP = (571.20 × 100) ÷ 68

⇒ MP = 57120 ÷ 68

⇒ MP = 840

∴ The correct answer is 840.

Additional Information

Successive Discount Formula

Total Discount % = d1 + d2 − (d1 × d2)/100. This is used for two successive discounts.

Relationship between SP and MP

Selling Price = Marked Price × (100 − Discount%)/100. If multiple discounts exist, multiply the factors successively.

Discount Value

Discount = Marked Price − Selling Price. It is always calculated on the Marked Price unless stated otherwise.

Question 41

At what temperature does water transform into steam under normal atmospheric pressure?  

  1. AOption (a)

    100°C (212°F) 

  2. BOption (b)

    50°C (122°F)  

  3. COption (c)

    80°C (176°F) 

  4. DOption (d)

    0°C (32°F) 

View answer & explanation

Correct answer

Answer: (a)A.

100°C (212°F) 

Why this answer is correct

The Correct answer is 100ºC (212ºF).

Key Points

  • Water transforms into steam at a temperature of 100ºC (212ºF) under normal atmospheric pressure, which is approximately 1 atm (101.325 kPa).
  • This process is called boiling, and it occurs when the vapor pressure of water equals the atmospheric pressure.
  • At the boiling point, water molecules gain enough kinetic energy to overcome intermolecular forces and transition from the liquid phase to the gaseous phase.
  • The boiling point of water can vary depending on altitude and pressure. At higher altitudes where pressure is lower, water boils at a temperature below 100ºC.
  • This temperature is widely used in science, cooking, and industrial applications to measure and control heat processes.
  • The boiling point of water is a crucial reference point in the Celsius temperature scale, where it is defined as 100ºC.

 Additional Information

  • 50ºC (122ºF)
  • This temperature is far below the boiling point of water under normal atmospheric pressure.
  • At 50ºC, water remains in the liquid state and is often considered warm but not hot enough for steam formation.
  • This temperature is commonly used in applications like heating water for bathing or other domestic uses.
  • 80ºC (176ºF)
  • 80ºC is still below the boiling point of water.
  • Water at this temperature is considered hot and is often used in cooking or beverage preparation, like making tea or coffee.
  • At this temperature, water may begin to exhibit signs of evaporation, but it does not boil or turn into steam under normal atmospheric pressure.
  • 0ºC (32ºF)
  • This is the freezing point of water under normal atmospheric pressure, not the boiling point.
  • At 0ºC, water transitions from a liquid to a solid, forming ice.
  • This temperature is a key reference in the Celsius and Fahrenheit scales.

Question 42

If AB = k + 3, BC = 2k and AC = 4k - 5, then for what value of ‘k’ does B lie on AC?  

  1. AOption (a)

    2

  2. BOption (b)

    5

  3. COption (c)

    3

  4. DOption (d)

    8

View answer & explanation

Correct answer

Answer: (d)D.

8

Why this answer is correct

Shortcut Trick

For Point B to lie on the line segment AC, the sum of segments AB and BC must be exactly equal to AC.

AB + BC = AC

(k + 3) + (2k) = 4k − 5

3k + 3 = 4k − 5

k = 8

∴ The correct answer is 8.

Alternate Method

Given:

Length of AB = k + 3

Length of BC = 2k

Length of AC = 4k − 5

Property used:

If three points A, B, and C are collinear and B lies between A and C, then by the Segment Addition Postulate, the total distance AC is the sum of the parts AB and BC.

Calculations:

⇒ AB + BC = AC

⇒ (k + 3) + 2k = 4k − 5

⇒ 3k + 3 = 4k − 5

⇒ 3 + 5 = 4k − 3k

⇒ 8 = k

∴ The correct answer is 8.

Additional Information

Collinearity of Points

Three points are collinear if they lie on the same straight line. For points A, B, and C, if AB + BC = AC, then B lies between A and C.

Triangle Inequality Theorem

In any triangle, the sum of any two sides must be greater than the third side (AB + BC > AC). If AB + BC = AC, the "triangle" degenerates into a straight line.

Distance Formula

In coordinate geometry, the distance between (x1, y1) and (x2, y2) is given by √((x2−x1)2 + (y2−y1)2).

Question 43

What will come in the place of '?” in the following equation, if ‘+’ and ‘-’ are interchanged and ‘×’ and ‘÷’ are interchanged?

24 × 6 ÷ 3 - 11 + 13 = ?

  1. AOption (a)

    9

  2. BOption (b)

    10

  3. COption (c)

    8

  4. DOption (d)

    12

View answer & explanation

Correct answer

Answer: (b)B.

10

Why this answer is correct

Given: 24 × 6 ÷ 3 - 11 + 13 = ?

According to the question, after ‘+’ and ‘-’ are interchanged and ‘×’ and ‘÷’ are interchanged:

24 × 6 ÷ 3 - 11 + 13 = ? ⇒ 24 ÷ 6 × 3 + 11 - 13 = ?

⇒ 24 ÷ 6 × 3 + 11 - 13 = ?

⇒ 4 × 3 + 11 - 13 = ?

⇒ 12 + 11 - 13 = ?

⇒ 23 - 13 = ?

⇒ 10 = ?

Hence, "Option 2" is the correct answer.

Question 44

If y3 = 0.008, then the value of y5 is:

  1. AOption (a)

    0.000032

  2. BOption (b)

    0.00032

  3. COption (c)

    0.032

  4. DOption (d)

    0.0032

View answer & explanation

Correct answer

Answer: (b)B.

0.00032

Why this answer is correct

Given:

y3 = 0.008

Formula used:

If yn = a, then y = a1/n

Calculations:

y3 = 0.008

⇒ y3 = (0.2)3

⇒ y = 0.2

Now, finding the value of y5:

⇒ y5 = (0.2)5

⇒ y5 = 0.2 × 0.2 × 0.2 × 0.2 × 0.2

⇒ y5 = 0.00032

∴ The correct answer is option (2).

Question 45

Select the set in which the numbers are related in the same way as are the numbers of the following sets.

(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 - Operations on 13 such as adding/subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

(7,28,56)

(9,36,72)

  1. AOption (a)

    (13, 52, 94)

  2. BOption (b)

    (11, 52, 104)

  3. COption (c)

    (13, 50, 104)

  4. DOption (d)

    (13, 52, 104)

View answer & explanation

Correct answer

Answer: (d)D.

(13, 52, 104)

Why this answer is correct

The logic followed here is:

Given:

(7,28,56)

7 × 4 + 28 = 56

28 + 28 = 56

56 = 56 (LHS = RHS)

And,

(9,36,72)

9 × 4 + 36 = 72

36 + 36 = 72

36 = 72 (LHS = RHS)

So, checking each option one by one:

Option 1) (13, 52, 94)

13 × 4 + 52 = 94

52 + 52 = 94

104 ≠ 94 (LHS ≠ RHS)

Option 2) (11, 52, 104)

11 × 4 + 52 = 104

44 + 52 = 104

96 ≠ 104 (LHS ≠ RHS)

Option 3) (13, 50, 104)

13 × 4 + 50 = 104

52 + 50 = 104

102 ≠ 104 (LHS ≠ RHS)

Option 4) (13, 52, 104)

13 × 4 + 52 = 104 

52 + 52 = 104 

104  = 104 (LHS = RHS)

Thus, out of all the options, '(13, 52, 104)' follows the same logic as given.

Hence, "Option 4" is the correct answer.

Question 46

 A can do a piece of work in 5 days. B can do it in 20 days. With the assistance of C, they completed the work in 2 days. C alone can do it in ______________days.

  1. AOption (a)

    4

  2. BOption (b)

    5

  3. COption (c)

    6

  4. DOption (d)

    3

View answer & explanation

Correct answer

Answer: (a)A.

4

Why this answer is correct

Shortcut Trick

Let the total work be the LCM of 5, 20, and 2 = 20 units.

Efficiency of A = 20 ÷ 5 = 4 units/day.

Efficiency of B = 20 ÷ 20 = 1 unit/day.

Combined efficiency of A + B + C = 20 ÷ 2 = 10 units/day.

Efficiency of C = 10 − (4 + 1) = 5 units/day.

Time taken by C alone = 20 ÷ 5 = 4 days.

∴ The correct answer is 4 days.

Alternate Method

Given:

Time taken by A = 5 days

Time taken by B = 20 days

Time taken by A + B + C = 2 days

Formula Used:

1/A + 1/B + 1/C = 1/Total Time

Calculations:

PersonDaysTotal WorkEfficiency
A5204
B201
A + B + C210

⇒ Efficiency of C = Efficiency of (A + B + C) − Efficiency of A − Efficiency of B

⇒ Efficiency of C = 10 − 4 − 1 = 5 units/day

⇒ Time taken by C alone = Total Work ÷ Efficiency of C

⇒ Time taken by C alone = 20 ÷ 5 = 4 days

∴ The correct answer is 4 days.

Additional Information

LCM Method for Time and Work

Total Work is assumed as the Least Common Multiple (LCM) of individual days. This avoids working with fractions and simplifies calculations.

Work and Efficiency Relation

Efficiency is inversely proportional to the time taken to complete a work. Efficiency = Work ÷ Time.

Question 47

In a certain code language, 'PAIN" is coded as '9315' and 'LIFT' is coded as '4256". What is the code for 'I' in the given code language?

  1. AOption (a)

    2

  2. BOption (b)

    1

  3. COption (c)

    5

  4. DOption (d)

    4

View answer & explanation

Correct answer

Answer: (c)C.

5

Why this answer is correct

The logic followed here is:

'PAIN" is coded as '9315'

'LIFT' is coded as '4256'

Thus, code for ‘I’ is '5'.

Hence, "Option 3" is the correct answer.

Question 48

Which part of the flower grows and ripens to form a fruit?

  1. AOption (a)

    Ovary

  2. BOption (b)

    Petal

  3. COption (c)

    Pollen tube

  4. DOption (d)

    Anther

View answer & explanation

Correct answer

Answer: (a)A.

Ovary

Why this answer is correct

The Correct answer is Ovary.

Key Points

  • The ovary is the part of a flower that develops into a fruit after fertilization.
  • It is located at the base of the pistil, which is the female reproductive structure of the flower.
  • Inside the ovary, there are one or more ovules, which contain the egg cells.
  • After pollination, the pollen grains fertilize the ovules, leading to the formation of seeds.
  • Once fertilization occurs, the ovary undergoes changes and ripens into a fruit, which helps in seed dispersal.
  • The fruit can be fleshy or dry, depending on the type of plant.
  • Examples of fruits formed from ripened ovaries include apples, mangoes, and tomatoes.
  • This process is essential for the reproduction and propagation of flowering plants.

 Additional Information

  • Petal
  • Petals are the colorful parts of a flower that attract pollinators such as bees, butterflies, and birds.
  • They do not play a direct role in the formation of fruits but are crucial for pollination.
  • Petals are part of the flower's corolla and act as a protective layer for the reproductive organs of the flower.
  • Pollen Tube
  • The pollen tube is a structure that forms after a pollen grain lands on the stigma of a flower.
  • It facilitates the transfer of male gametes from the pollen grain to the ovule.
  • While it is essential for fertilization, it does not ripen or develop into a fruit.
  • Anther
  • The anther is the part of the flower's male reproductive system where pollen grains are produced.
  • It is located at the tip of the stamen and is responsible for dispersing pollen.
  • Anthers do not contribute to the formation of fruits; their primary role is in pollination.

Question 49

Burning of unsaturated compounds gives which of the following?

  1. AOption (a)

    Green flame

  2. BOption (b)

    Red flame

  3. COption (c)

    Yellow flame

  4. DOption (d)

    Clean flame

View answer & explanation

Correct answer

Answer: (c)C.

Yellow flame

Why this answer is correct

The Correct answer is Yellow Flame.

Key Points

  • When unsaturated compounds such as alkenes and alkynes undergo combustion, they generally produce a yellow flame.
  • The yellow flame is caused by the incomplete combustion of hydrocarbons, which leads to the formation of soot particles.
  • Unsaturated hydrocarbons contain double or triple bonds between carbon atoms, which require more oxygen for complete combustion compared to saturated hydrocarbons.
  • Due to insufficient oxygen supply during burning, the combustion is incomplete, resulting in the release of carbon particles that glow yellow when heated.
  • Examples of unsaturated hydrocarbons include ethylene (C2H4) and acetylene (C2H2).
  • The yellow flame is often observed in laboratory experiments when burning hydrocarbons with limited oxygen availability.

 Additional Information

  • Green Flame
  • A green flame is not typically produced by the combustion of hydrocarbons. It is usually observed when certain elements like copper or boron compounds burn, as these elements emit green light due to their specific emission spectra.
  • For example, the combustion of copper salts in a flame produces a green color.
  • Red Flame
  • A red flame is associated with the combustion of certain elements like strontium or lithium compounds.
  • It is not related to the burning of hydrocarbons, whether saturated or unsaturated.
  • Clean Flame
  • A clean flame is typically produced by the complete combustion of saturated hydrocarbons like methane or propane.
  • Complete combustion occurs when there is a sufficient supply of oxygen, resulting in no soot and the production of carbon dioxide and water vapor.

Question 50

Project PARI is an initiative launched by which of the following organisations/Ministries to celebrate and enhance the public art scene in India?

  1. AOption (a)

    Lalit Kala Akademi 

  2. BOption (b)

    Union Ministry of Culture

  3. COption (c)

    Centre for Cultural Resources and Training (CCRT)

  4. DOption (d)

    Sahitya Akademi

View answer & explanation

Correct answer

Answer: (b)B.

Union Ministry of Culture

Why this answer is correct

The Correct answer is Union Ministry of Culture.

Key Points

  • Project PARI (Public Art for Resilient India) is an initiative launched by the Union Ministry of Culture to celebrate and enhance the public art scene in India.
  • The project aims to promote public engagement with art and provide a platform for local and contemporary artists to showcase their creativity in public spaces.
  • The initiative is part of the government's larger effort to integrate art and culture into everyday life, thereby fostering a sense of pride and ownership among citizens.
  • It emphasizes the preservation and promotion of India's rich cultural heritage while also embracing modern and innovative art forms.
  • Through Project PARI, the Ministry seeks to transform urban and rural landscapes by installing public artworks that reflect the diversity and dynamism of Indian culture.
  • The initiative aligns with the 'Ek Bharat Shreshtha Bharat' program, which aims to strengthen cultural unity and collaboration across the country.

 Additional Information

  • Lalit Kala Akademi
  • The Lalit Kala Akademi, also known as the National Academy of Art, is an autonomous organization under the Ministry of Culture.
  • It was established in 1954 to promote and propagate understanding of Indian visual arts, such as painting, sculpture, and graphics.
  • It organizes art exhibitions, workshops, and camps and also provides scholarships and awards to artists.
  • However, it is not directly involved in public art initiatives like Project PARI.
  • Centre for Cultural Resources and Training (CCRT)
  • The CCRT is an autonomous organization under the Ministry of Culture, established in 1979.
  • Its primary objective is to promote the integration of culture and education by providing training to school teachers and students in cultural heritage.
  • It is not directly involved in public art projects but focuses on educational and cultural enrichment programs.
  • Sahitya Akademi
  • The Sahitya Akademi, also known as the National Academy of Letters, is dedicated to the promotion of literature in India.
  • Established in 1954, it recognizes and awards excellence in Indian literature across various languages.
  • It primarily focuses on literary works and activities, not public art or visual arts.

Question 51

What happens to the motion of an object when balanced forces act on it? 

  1. AOption (a)

    Its state of motion remains unchanged. 

  2. BOption (b)

    It changes its direction of motion.  

  3. COption (c)

    It speeds up. 

  4. DOption (d)

    It slows down. 

View answer & explanation

Correct answer

Answer: (a)A.

Its state of motion remains unchanged. 

Why this answer is correct

The Correct answer is Its state of motion remains unchanged.

Key Points

  • Balanced forces are forces that are equal in magnitude but act in opposite directions.
  • When balanced forces act on an object, the net force becomes zero.
  • An object remains in its current state of motion (either at rest or in uniform motion) when no net force acts on it, as per Newton's First Law of Motion.
  • This phenomenon is often referred to as the law of inertia, which states that an object will continue in its existing state unless acted upon by an unbalanced force.
  • For example, if a book is lying on a table and balanced forces act on it (gravity and the table's upward force), the book remains stationary.
  • Similarly, if an object is moving in a straight line with constant speed and balanced forces act on it, its motion remains unchanged.
  • Balanced forces do not cause any acceleration, change in direction, or deformation of the object.

 Additional Information

  • It changes its direction of motion.
  • Forces can change the direction of motion, but this happens only when the forces are unbalanced, not balanced.
  • Unbalanced forces produce a net force that can alter the trajectory of the object.
  • It speeds up.
  • An object speeds up when unbalanced forces act on it, causing acceleration.
  • Balanced forces do not lead to any change in the speed or velocity of an object.
  • It slows down.
  • Slowing down or deceleration occurs due to unbalanced forces, such as friction or resistance.
  • Balanced forces cannot decrease an object's speed because there is no net force acting on it.

Question 52

Simplify the following expression:  

cos⁡θ1−sin⁡θ+1−sin⁡θcos⁡θ\frac{\cos \theta}{1-\sin \theta}+\frac{1-\sin \theta}{\cos \theta}

  1. AOption (a)

    1 + 2 sin θ 

  2. BOption (b)

    2 cos θ 

  3. COption (c)

    2 sin θ 

  4. DOption (d)

    2 sec θ 

View answer & explanation

Correct answer

Answer: (d)D.

2 sec θ 

Why this answer is correct

Shortcut Trick

Put θ = 0° to simplify the expression quickly.

When θ = 0°, cos 0° = 1 and sin 0° = 0.

Expression = (1 / (1 − 0)) + ((1 − 0) / 1) = 1 + 1 = 2.

Check options: 2 sec 0° = 2 × 1 = 2.

∴ The correct answer is 2 sec θ.

Alternate Method

Given: cos⁡θ1−sin⁡θ+1−sin⁡θcos⁡θ\frac{\cos \theta}{1-\sin \theta}+\frac{1-\sin \theta}{\cos \theta}

Formula Used: sin2 θ + cos2 θ = 1; sec θ = 1/cos θ

⇒ Taking LCM: [cos2 θ + (1 − sin θ)2] / [cos θ(1 − sin θ)]

⇒ Expanding (1 − sin θ)2: [cos2 θ + 1 + sin2 θ − 2 sin θ] / [cos θ(1 − sin θ)]

⇒ Using Identity (sin2 θ + cos2 θ = 1): [1 + 1 − 2 sin θ] / [cos θ(1 − sin θ)]

⇒ [2 − 2 sin θ] / [cos θ(1 − sin θ)]

⇒ [2(1 − sin θ)] / [cos θ(1 − sin θ)]

⇒ 2 / cos θ = 2 sec θ

∴ The correct answer is 2 sec θ.

Additional Information

Trigonometric Identities

Primary identities: sin2θ + cos2θ = 1, 1 + tan2θ = sec2θ, and 1 + cot2θ = cosec2θ.

Reciprocal Relations

sec θ = 1/cos θ, cosec θ = 1/sin θ, and cot θ = 1/tan θ.

Question 53

Read the given statements and conclusions carefully. You have to take the given statements to be true even if they seem to be at variance from commonly known facts and decide which conclusion(s) logically follow(s) from the given statements.

Statements:

All watches are perfumes.

No watch is a tie.

Conclusions:

(I) All perfumes are watches.

(II) No perfume is a tie.

  1. AOption (a)

    Only conclusion I follows

  2. BOption (b)

    Neither conclusion I nor II follows 

  3. COption (c)

    Both conclusions I and II follow

  4. DOption (d)

    Only conclusion II follows

View answer & explanation

Correct answer

Answer: (b)B.

Neither conclusion I nor II follows 

Why this answer is correct

The least possible Venn diagram for the given statements is as shown below :

Conclusions:

(I) All perfumes are watches → Does not follow (As all watches are perfumes. So it is possible but not definite.)

(II) No perfume is a tie → Does not follow (As all watches are perfumes and no watch is a tie. As no direct relation is given between perfumes and tie, therefore it is false)

∴ Here, Neither conclusion I nor II follows.​

Hence, the correct answer is "Option 2"

Question 54

In 2024, what major upgrade did the Indian Air Force (IAF) focus on to enhance its defense capabilities?

  1. AOption (a)

    Acquisition of advanced drones for surveillance

  2. BOption (b)

    Upgrading the Sukhoi-30MKI fleet with new avionics

  3. COption (c)

    Expansion of the cyber defense unit

  4. DOption (d)

    Development of indigenously produced submarines

View answer & explanation

Correct answer

Answer: (b)B.

Upgrading the Sukhoi-30MKI fleet with new avionics

Why this answer is correct

The Correct answer is Upgrading the Sukhoi-30MKI fleet with new avionics.

Key Points

  • The Sukhoi-30MKI, a multirole fighter aircraft, serves as the backbone of the Indian Air Force.
  • The upgrade in 2024 focused on equipping the Sukhoi-30MKI fleet with advanced avionics systems, enhancing its combat readiness and operational capabilities.
  • The new avionics include radar systems, electronic warfare suites, and advanced communication systems, which make the aircraft more effective in modern warfare scenarios.
  • This upgrade ensures better integration with indigenous weapon systems, such as the BrahMos supersonic missile, making the aircraft a formidable platform for strategic missions.
  • The project aligns with the government's ‘Make in India’ initiative, as many components of the upgrade are manufactured indigenously.
  • The upgrade enhances the ability to counter aerial threats, undertake long-range missions, and perform precision strikes.
  • The modernization of the Sukhoi-30MKI fleet represents a critical step toward strengthening India's air superiority and addressing emerging challenges in the region.
  • The Indian Air Force has partnered with Hindustan Aeronautics Limited (HAL) to implement these upgrades efficiently.

 Additional Information

  • Acquisition of advanced drones for surveillance
  • Drones are unmanned aerial vehicles (UAVs) used for a variety of purposes, including surveillance, reconnaissance, and combat missions.
  • While the IAF is indeed expanding its drone capabilities, the focus in 2024 was more on upgrading existing platforms like the Sukhoi-30MKI.
  • India has made significant advancements in indigenous drone development, such as the DRDO's Rustom series and other UAV projects.
  • Expansion of the cyber defense unit
  • Cyber defense is critical in modern warfare to protect sensitive data and operational systems from cyber-attacks.
  • The IAF has been working on strengthening its cybersecurity infrastructure, but this was not the primary focus in 2024.
  • Cyber defense involves deploying firewalls, encryption systems, and AI-driven monitoring tools to safeguard communication networks.
  • Development of indigenously produced submarines
  • Submarine development is primarily the responsibility of the Indian Navy, not the Indian Air Force.
  • India has been working on its indigenous submarine programs, such as the INS Arihant, under the Strategic Forces Command.
  • Submarines are crucial for maritime security, underwater reconnaissance, and nuclear deterrence capabilities.

Question 55

The displacement of a body is perpendicular to the direction in which the force is applied; the work done in this case will be:

  1. AOption (a)

    Infinite

  2. BOption (b)

    Positive

  3. COption (c)

    Zero

  4. DOption (d)

    Negative

View answer & explanation

Correct answer

Answer: (c)C.

Zero

Why this answer is correct

The correct answer is Zero.

Key Points

  • Work done is determined by the formula: W = F × d × cos(θ), where:
  • W is the work done,
  • F is the magnitude of the force applied,
  • d is the displacement of the object,
  • θ is the angle between the force and displacement.
  • When the displacement is perpendicular to the direction of the force, the angle θ becomes 90 degrees.
  • The cosine of 90 degrees is equal to 0. Hence, the work done (W) becomes 0, regardless of the magnitude of force or displacement.
  • This is because there is no component of force acting in the direction of the displacement when the two are perpendicular.
  • Examples of such cases include:
  • Carrying a bag horizontally while walking forward – the force exerted (vertically upward) by the arms is perpendicular to the horizontal displacement.
  • Motion of a satellite in a circular orbit – the force (gravitational) is perpendicular to the displacement.

 Additional Information

  • Infinite
  • The term infinite work is not applicable in real-world physics as it defies the laws of energy conservation.
  • Work is always a finite quantity, based on the force applied and the displacement.
  • Positive
  • Work is considered positive when the force and displacement are in the same direction.
  • For example, pushing a box forward applies a force in the direction of displacement, resulting in positive work.
  • Negative
  • Work is considered negative when the force and displacement are in opposite directions.
  • For instance, when braking a car, the frictional force acts in the opposite direction to the car's displacement, resulting in negative work.

Question 56

Organisms whose cells lack a nuclear membrane are called _______.

  1. AOption (a)

    eukaryotes

  2. BOption (b)

    prokaryotes

  3. COption (c)

    cytoplasm

  4. DOption (d)

    chromatin

View answer & explanation

Correct answer

Answer: (b)B.

prokaryotes

Why this answer is correct

The Correct answer is prokaryotes.

Key Points

  • Prokaryotes are organisms whose cells lack a well-defined nuclear membrane, meaning their genetic material is not enclosed within a nucleus.
  • Their genetic material, usually in the form of a single circular DNA molecule, floats freely in a region called the nucleoid.
  • Prokaryotic cells are simpler in structure and lack membrane-bound organelles such as the nucleus, mitochondria, and Golgi apparatus.
  • Examples of prokaryotic organisms include bacteria (e.g., Escherichia coli) and archaea (e.g., Halobacterium).
  • The absence of a nuclear membrane allows prokaryotes to carry out cellular processes efficiently as their genetic material is easily accessible for replication and transcription.
  • Prokaryotes are generally smaller in size (usually ranging from 0.1 to 5 micrometers) compared to eukaryotic cells.
  • They reproduce primarily through an asexual process called binary fission.

 Additional Information

  • Eukaryotes
  • Eukaryotic cells possess a well-defined nucleus enclosed by a nuclear membrane.
  • They contain membrane-bound organelles such as mitochondria, chloroplasts, and the endoplasmic reticulum.
  • Examples of eukaryotic organisms include plants, animals, fungi, and protists.
  • Eukaryotic cells are generally larger in size, ranging from 10 to 100 micrometers.
  • Cytoplasm
  • The cytoplasm is the gel-like substance inside the cell where various cellular components and organelles are suspended.
  • It plays a crucial role in facilitating cellular processes such as growth, metabolism, and replication.
  • Chromatin
  • Chromatin is the complex of DNA and proteins found in the nucleus of eukaryotic cells.
  • It condenses to form chromosomes during cell division.

Question 57

If a 4-digit number 12z4 is divisible by 4, then the greatest possible value of ‘z’ is: 

  1. AOption (a)

    8

  2. BOption (b)

    2

  3. COption (c)

    6

  4. DOption (d)

    4

View answer & explanation

Correct answer

Answer: (a)A.

8

Why this answer is correct

Shortcut Trick

For a number to be divisible by 4, its last two digits must be divisible by 4.

The last two digits of 12z4 are z4.

Possible values for z (where z4 is divisible by 4): 0, 2, 4, 6, 8.

The greatest possible value among these is 8.

∴ The correct answer is 8.

Alternate Method

Given: 4-digit number = 12z4, Divisor = 4.

Formula Used: Divisibility rule of 4 → Last two digits of the number must be a multiple of 4.

⇒ Last two digits = z4 (representing 10z + 4)

⇒ For z = 9: 94 ÷ 4 = 23.5 (No)

⇒ For z = 8: 84 ÷ 4 = 21 (Yes)

⇒ Since 8 is the largest single-digit integer satisfying the condition, z = 8.

∴ The correct answer is 8.

Additional Information

Divisibility by 2n

For 21 (2), last 1 digit must be even. For 22 (4), last 2 digits must be divisible by 4. For 23 (8), last 3 digits must be divisible by 8.

Divisibility by 3 and 9

A number is divisible by 3 or 9 if the sum of its digits is divisible by 3 or 9 respectively.

Question 58

Which one of the following options is correctly paired according to their mode of action? 

  1. AOption (a)

    Contraceptive pills — Uterine device 

  2. BOption (b)

    Copper T — Hormonal imbalance 

  3. COption (c)

    Tubectomy — Chemical barrier 

  4. DOption (d)

    Condom — Mechanical barrier 

View answer & explanation

Correct answer

Answer: (d)D.

Condom — Mechanical barrier 

Why this answer is correct

The Correct answer is Condom — Mechanical barrier.

Key Points

  • Condoms act as a mechanical barrier by physically preventing the sperm from reaching the egg, thereby avoiding fertilization.
  • They are made of materials such as latex, polyurethane, or lambskin, which provide an effective barrier to sperm and sexually transmitted infections (STIs).
  • Condoms are one of the most widely used contraceptive methods and are effective in preventing unintended pregnancies and reducing the risk of HIV/AIDS and other STIs.
  • They are easy to use, widely available, and do not require a prescription, making them a popular choice worldwide.
  • Both male and female condoms are available, but male condoms are more commonly used.
  • Condoms do not involve hormones, which makes them suitable for individuals who cannot or do not want to use hormonal contraceptives.

 Additional Information

  • Contraceptive pills — Uterine device
  • This is incorrect because contraceptive pills do not act as uterine devices. Instead, they contain hormones (estrogen and progestin) that prevent ovulation, thicken cervical mucus, and thin the uterine lining to avoid pregnancy.
  • Contraceptive pills are an example of hormonal contraception, not a physical device.
  • Copper T — Hormonal imbalance
  • This is incorrect because Copper T is a type of intrauterine device (IUD) that works by releasing copper ions, which are toxic to sperm. It does not cause hormonal imbalance.
  • Copper IUDs are non-hormonal and function as a long-term reversible contraceptive method.
  • Tubectomy — Chemical barrier
  • This is incorrect because tubectomy is a form of permanent surgical sterilization in females. It involves blocking or cutting the fallopian tubes to prevent the egg from reaching the uterus.
  • It is not a chemical barrier but a surgical procedure.

Question 59

Identify the process with the given description.

The seed contains the future plant or embryo which develops into a seedling under appropriate conditions’.

  1. AOption (a)

    Regeneration 

  2. BOption (b)

    Fermentation 

  3. COption (c)

    Plantation 

  4. DOption (d)

    Germination 

View answer & explanation

Correct answer

Answer: (d)D.

Germination 

Why this answer is correct

The Correct answer is Germination.

Key Points

  • Germination is the process by which a seed develops into a new plant or seedling under suitable conditions.
  • The seed contains an embryo, which is the future plant, along with stored nutrients that support its initial growth.
  • During germination, the seed absorbs water in a process called imbibition, which activates the enzymes needed for growth.
  • After water absorption, the seed swells, and the radicle (embryonic root) emerges first, anchoring the plant to the soil.
  • Next, the plumule (embryonic shoot) emerges and begins growing upward toward the light.
  • The process requires specific conditions such as adequate water, oxygen, and a suitable temperature range to take place.
  • Germination is critical for plant reproduction and helps ensure the continuation of plant species.
  • Examples of seeds undergoing germination are those of wheat, rice, and beans.

 Additional Information

  • Regeneration
  • Regeneration refers to the process by which organisms regrow lost or damaged tissues, organs, or limbs.
  • This is observed in some animals like starfish, lizards, and planarians, but not in plants as a primary growth process.
  • In plants, regeneration can occur in tissues during vegetative propagation, but it is distinct from germination.
  • Fermentation
  • Fermentation is a metabolic process where microorganisms like bacteria or yeast convert sugars into alcohol, gases, or acids.
  • It is commonly used in the production of alcoholic beverages, bread, and yogurt.
  • This process is unrelated to the growth of plants from seeds.
  • Plantation
  • Plantation refers to the act of planting trees or crops over a large area.
  • It is a method of cultivation for crops like tea, coffee, and rubber, rather than a natural growth process like germination.

Question 60

Where was the Ministry of Coal’s first-ever coal gallery, an exhibition titled ‘Black Diamond: Unveiling the Depths,’ inaugurated in October 2024? 

  1. AOption (a)

    Dhanbad

  2. BOption (b)

    Ranchi

  3. COption (c)

    Raipur

  4. DOption (d)

    New Delhi

View answer & explanation

Correct answer

Answer: (d)D.

New Delhi

Why this answer is correct

The Correct answer is New Delhi.

Key Points

  • The Ministry of Coal inaugurated its first-ever coal gallery titled 'Black Diamond: Unveiling the Depths' in New Delhi in October 2024.
  • This gallery showcases the rich history, importance, and significance of coal mining in India.
  • New Delhi, as the capital city, is a hub for major government initiatives, exhibitions, and cultural events, making it a suitable location for this gallery.
  • The exhibition is aimed at educating people about the role of coal in India's energy sector and its impact on the nation's economy.
  • It also highlights advancements in coal mining technologies and measures for sustainable mining practices.
  • The Ministry of Coal's efforts in creating this gallery align with its initiative to promote awareness and innovation in the coal sector.

 Additional Information

  • Dhanbad
  • Dhanbad is referred to as the 'Coal Capital of India' due to its extensive coal mining activities.
  • It is home to major coalfields such as the Jharia and Raniganj coalfields.
  • The city hosts the Indian School of Mines, a premier institute focusing on mining education.
  • Ranchi
  • Ranchi is the capital of Jharkhand, a state rich in mineral resources including coal.
  • The city is a major administrative center for coal-related industries and is close to major coal mining areas.
  • Raipur
  • Raipur is the capital of Chhattisgarh, another state with significant coal reserves.
  • It is known for its industrial importance and proximity to coal mining regions like Korba.

Question 61

If each vowel in the word PLASTID is changed to the letter following it in the English alphabetical order and each consonant is changed to the letter preceding it in the English alphabetical order, and the set of letters thus arrived are then rearranged in reverse of English alphabetical order, then which of the following letters will be third from the left in the group of letter thus formed? 

  1. AOption (a)

    R

  2. BOption (b)

    K

  3. COption (c)

    H

  4. DOption (d)

    O

View answer & explanation

Correct answer

Answer: (d)D.

O

Why this answer is correct

Given word: PLASTID

According to the question,

Given wordPLASTID
Vowel → (+1) Consonant → (-1)(-1)(-1)(+1)(-1)(-1)(+1)(-1)
ResultantOKBRSJC
Arranged in reverse English alphabetical orderSROKJCB

Thus, the new formed letter cluster → S R O K J C B

So, third from the left in the group of letters thus formed: (Left end) S R O K J C B (Right end) → O

Hence, "Option 4" is the correct answer.

Question 62

Find the greatest number by which when the numbers 57, 95 and 211 are divided, it leaves the same reminder in each case. 

  1. AOption (a)

    2

  2. BOption (b)

    3

  3. COption (c)

    1

  4. DOption (d)

    4

View answer & explanation

Correct answer

Answer: (a)A.

2

Why this answer is correct

Shortcut Trick

For the same remainder, the required greatest number is the HCF of the absolute differences between the numbers.

Numbers: 57, 95, 211

Differences: (95 − 57) = 38; (211 − 95) = 116; (211 − 57) = 154

HCF(38, 116, 154): 38 = 2 × 19; 116 = 2 × 58; 154 = 2 × 77

The only common factor is 2.

∴ The correct answer is 2.

Alternate Method

Given: Numbers are 57, 95, and 211.

Formula Used: Required Number = HCF(|x − y|, |y − z|, |z − x|)

⇒ First difference = 95 − 57 = 38

⇒ Second difference = 211 − 95 = 116

⇒ Third difference = 211 − 57 = 154

⇒ Factors of 38 = 1, 2, 19, 38

⇒ Factors of 116 = 1, 2, 4, 29, 58, 116

⇒ Factors of 154 = 1, 2, 7, 11, 14, 22, 77, 154

⇒ Highest Common Factor (HCF) = 2

∴ The correct answer is 2.

Additional Information

HCF with same remainder

When the remainder is the same but unknown, calculate the HCF of the differences between the given numbers: HCF(|a−b|, |b−c|, |c−a|).

HCF with different remainders

To find the greatest number that divides a, b, c leaving remainders r1, r2, r3, calculate HCF(a−r1, b−r2, c−r3).

LCM Property

LCM is the smallest number exactly divisible by all given numbers. For a remainder 'r' in each case, the number is LCM(a, b, c) + r.

Question 63

The ratio between the present ages of Amit and Amita is 7 : 5, respectively. The ratio between Amit’s age 5 years ago and Amita's age 5 years hence is 1 : 1. What is the sum of the present age of Amit and Amita?  

  1. AOption (a)

    40 years 

  2. BOption (b)

    70 years 

  3. COption (c)

    60 years 

  4. DOption (d)

    50 years 

View answer & explanation

Correct answer

Answer: (c)C.

60 years 

Why this answer is correct

Shortcut Trick

Ratio of present ages of Amit and Amita = 7 : 5

Difference in ratio parts (7 − 5) = 2 units

As per condition: (7 units − 5) = (5 units + 5) ⇒ 2 units = 10 years

Sum of present ages (7 + 5) = 12 units

If 2 units = 10 years, then 12 units = 10 × 6 = 60 years

∴ The correct answer is 60 years.

Alternate Method

Given:

Ratio of present ages of Amit and Amita = 7 : 5

Let Amit present age = 7x and Amita present age = 5x

Calculations:

⇒ (Amit age 5 years ago) / (Amita age 5 years hence) = 1 / 1

⇒ (7x − 5) / (5x + 5) = 1 / 1

⇒ 7x − 5 = 5x + 5

⇒ 7x − 5x = 5 + 5

⇒ 2x = 10

⇒ x = 5

⇒ Sum of present ages = 7x + 5x = 12x

⇒ Sum = 12 × 5 = 60 years

∴ The correct answer is 60 years.

Additional Information

Ratio and Proportions in Ages

When a constant number of years is added or subtracted, the absolute difference between two people's ages remains constant.

Cross-Multiplication Method

Useful for solving age problems where two different ratios at two different time points are provided: (a/b) → (c/d) over 'n' years.

Question 64

What are the balanced products of the following reaction?  

Na2SO4(aq) + BaCl2 (aq) → _______ + ________

  1. AOption (a)

    BaSO4(s) + 2NaCl2 (aq)

  2. BOption (b)

    BaSO2(s) + NaCl (aq) + O2(g)

  3. COption (c)

    BaSO2(s) + NaCl (aq) + 2O2​(g)

  4. DOption (d)

    BaSO4(s) + 2NaCl (aq)

View answer & explanation

Correct answer

Answer: (d)D.

BaSO4(s) + 2NaCl (aq)

Why this answer is correct

The Correct answer is BaSO4(s) + 2NaCl (aq).

Key Points

  • The reaction between sodium sulfate (Na2SO4) and barium chloride (BaCl2) is a classic example of a double displacement reaction.
  • In this reaction, the sulfate ion (SO42−) from sodium sulfate reacts with the barium ion (Ba2+) from barium chloride to form an insoluble compound, barium sulfate (BaSO4), which precipitates as a solid.
  • The balanced equation for the reaction is: Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq).
  • Barium sulfate (BaSO4) is a white precipitate, and its formation is used as an analytical test for the presence of sulfate ions.
  • The other product, sodium chloride (NaCl), remains in the solution as an aqueous compound.
  • This reaction demonstrates the principle of precipitation reactions, where an insoluble substance (precipitate) is formed when two aqueous solutions are mixed.

 Additional Information

  • BaSO4(s) + 2NaCl2 (aq)
  • This option is incorrect because the formula "NaCl2" is not valid. Sodium chloride (NaCl) is a simple ionic compound, and sodium does not form NaCl2.
  • BaSO2(s) + NaCl (aq) + O2(g)
  • This option is incorrect because BaSO2 is not a product of this reaction. Moreover, no gas like O2 is released in this double displacement reaction.
  • BaSO2(s) + NaCl (aq) + 2O2(g)
  • This option is incorrect for the same reasons as the previous one. The compound BaSO2 does not form, and oxygen gas is not evolved in this reaction.

Question 65

Which of the following symbols were used by Bohr to represent different electron orbits in his atomic model? 

  1. AOption (a)

    A, B, C, D, E....

  2. BOption (b)

    W, X,. Y, Z, A....

  3. COption (c)

    R, S, T, U, V...

  4. DOption (d)

    K, L, M, N, O...

View answer & explanation

Correct answer

Answer: (d)D.

K, L, M, N, O...

Why this answer is correct

The Correct answer is K, L, M, N, O...

Key Points

  • Niels Bohr, in his atomic model, represented different electron orbits or energy levels using the symbols K, L, M, N, O....
  • These orbits correspond to the principal quantum numbers (n = 1, 2, 3, 4, 5...) and represent specific energy levels around the nucleus.
  • Each orbit is associated with a specific energy state, with the K-shell (n=1) being the closest to the nucleus and having the lowest energy.
  • This representation helped in understanding the distribution of electrons in an atom and their arrangement across various energy levels.
  • The concept of energy levels (or shells) is crucial in explaining the chemical properties of elements and the formation of bonds.
  • The naming convention (K, L, M, N...) was adopted to avoid confusion with the alphabetical representation of other atomic properties like subshells (s, p, d, f).
  • This model laid the foundation for the modern quantum mechanical model of the atom.

Question 66

If + means -, - means ×, × means ÷, and ÷ means +, then what will come in place of the question mark (?) in the following equation?

27 ÷ 66 × 11 - 7 + 10 = ?

  1. AOption (a)

    60

  2. BOption (b)

    59

  3. COption (c)

    56

  4. DOption (d)

    58

View answer & explanation

Correct answer

Answer: (b)B.

59

Why this answer is correct

Decoding signs:

Sign+-×÷
Stands for-×÷+

Given: 27 ÷ 66 × 11 - 7 + 10 = ?

After interchanging the letters,

27 ÷ 66 × 11 - 7 + 10 = ? ⇒ 27 + 66 ÷ 11 × 7 - 10 = ?

⇒ 27 + 66 ÷ 11 × 7 - 10 = ?

⇒ 27 + 6 × 7 - 10 = ?

⇒ 27 + 42 - 10 = ?

⇒ 69 - 10 = ?

⇒ 59 = ?

Hence, "Option 2" is the correct answer.

Question 67

Who was appointed as the Head Coach of the Indian men’s cricket team in July 2024?

  1. AOption (a)

    Gautam Gambhir 

  2. BOption (b)

    Rahul Dravid

  3. COption (c)

    VVS Laxman

  4. DOption (d)

    MS Dhoni

View answer & explanation

Correct answer

Answer: (a)A.

Gautam Gambhir 

Why this answer is correct

The Correct answer is Gautam Gambhir.

Key Points

  • Gautam Gambhir is a former Indian cricketer and one of the most celebrated batsmen in Indian cricket history.
  • He played a crucial role in India's triumphs in both the 2007 ICC T20 World Cup and the 2011 ICC Cricket World Cup, making significant contributions in the finals.
  • Gambhir is known for his determined batting style and ability to perform under pressure.
  • Post-retirement, he has been actively involved in cricket commentary, analysis, and mentoring young cricketers.
  • His appointment as the Head Coach of the Indian men's cricket team in July 2024 highlights his deep understanding of the game and leadership qualities.
  • Gautam Gambhir has also been involved in politics, representing Bharatiya Janata Party (BJP) and serving as a Member of Parliament from East Delhi Constituency.
  • His dual experience in sports and leadership roles makes him a capable figure to guide the Indian cricket team.

 Additional Information

  • Rahul Dravid
  • Rahul Dravid is the current head coach of the Indian team as of 2023 and a legendary cricketer known as "The Wall" for his solid batting.
  • He has previously served as the coach for India’s Under-19 team, guiding them to win the 2018 ICC Under-19 World Cup.
  • Dravid is an iconic figure in Indian cricket and has played a significant role in mentoring young talent.
  • VVS Laxman
  • VVS Laxman is another former Indian cricketer known for his elegant batting style and exceptional performances, especially in Test cricket.
  • He serves as the Head of the National Cricket Academy (NCA) in Bengaluru and has contributed to nurturing upcoming players.
  • Laxman’s mentorship has been instrumental in shaping the next generation of Indian cricketers.
  • MS Dhoni
  • MS Dhoni is one of India’s most successful cricket captains, known for his calm demeanor and finishing abilities.
  • He led India to victory in the 2007 ICC T20 World Cup, 2011 ICC Cricket World Cup, and the 2013 ICC Champions Trophy.
  • Dhoni retired from international cricket in 2020 but continues to play in the Indian Premier League (IPL) for the Chennai Super Kings.

Question 68

Which of the options below represents the correct chemical formula of calcium hydroxide? 

  1. AOption (a)

    Ca(OH)2

  2. BOption (b)

    Mg(OH)2

  3. COption (c)

    KOH

  4. DOption (d)

    NaOH

View answer & explanation

Correct answer

Answer: (a)A.

Ca(OH)2

Why this answer is correct

The Correct answer is Ca(OH)₂.

Key Points

  • Calcium hydroxide has the chemical formula Ca(OH)₂. It consists of one calcium atom (Ca) bonded to two hydroxide ions (OH).
  • It is commonly known as slaked lime and is widely used in various industries, including construction, agriculture, and water treatment.
  • Calcium hydroxide is produced when calcium oxide (quicklime) reacts with water in an exothermic reaction.
  • The compound is slightly soluble in water and forms a solution known as lime water, which is often used to test for the presence of carbon dioxide.
  • Ca(OH)₂ is a strong base and reacts with acids to form salts and water, making it useful in neutralizing acidic solutions.
  • It is also used in the preparation of mortars and plasters due to its ability to set and harden when exposed to carbon dioxide.

 Additional Information

  • Mg(OH)₂
  • Magnesium hydroxide has the chemical formula Mg(OH)₂ and is commonly known as milk of magnesia.
  • It is used as an antacid to relieve indigestion and heartburn and as a laxative for treating constipation.
  • Magnesium hydroxide is less soluble in water compared to calcium hydroxide.
  • KOH
  • Potassium hydroxide is a strong base with the chemical formula KOH.
  • It is used in the production of soaps, detergents, and fertilizers.
  • KOH is highly soluble in water and forms a strongly alkaline solution.
  • NaOH
  • Sodium hydroxide, also known as caustic soda, has the chemical formula NaOH.
  • It is widely used in industries such as paper, textiles, and cleaning agents.
  • NaOH is highly corrosive and is a strong base.

Question 69

Refer to the given series and answer the question that follows (all numbers are single-digit numbers only, and all counting is to be done from left to right).

(Left) 7 2 5 5 2 1 9 2 4 1 2 2 6 9 5 5 5 3 8 5 5 3 1 1 6 3 3 (Right)

How many such even digits are there, each of which is immediately preceded by a perfect square and immediately followed by an even digit? (Note: 1 will be considered as a perfect square.)

  1. AOption (a)

    1

  2. BOption (b)

    2

  3. COption (c)

    3

  4. DOption (d)

    0

View answer & explanation

Correct answer

Answer: (b)B.

2

Why this answer is correct

Given series: (Left) 7 2 5 5 2 1 9 2 4 1 2 2 6 9 5 5 5 3 8 5 5 3 1 1 6 3 3 (Right)

According to the question, such even digit which are immediately preceded by a perfect square and is immediately followed by an even digit:

Required condition: Perfect square - Even digit - Even digit

(Left) 7 2 5 5 2 1 9 2 4 1 2 2 6 9 5 5 5 3 8 5 5 3 1 1 6 3 3 (Right)

Thus, there are two such even digit which are immediately preceded by a perfect square and is immediately followed by an even digit.

Hence, "Option 2" is the correct answer.

Question 70

Which of the following represents the molecular formula for carbon monoxide?

  1. AOption (a)

    CO3

  2. BOption (b)

    CO2

  3. COption (c)

    C2O

  4. DOption (d)

    CO

View answer & explanation

Correct answer

Answer: (d)D.

CO

Why this answer is correct

The Correct answer is CO.

Key Points

  • The molecular formula CO represents Carbon Monoxide, a compound composed of one carbon atom and one oxygen atom.
  • Carbon Monoxide is a colorless, odorless, and tasteless gas that is highly toxic to humans and animals when inhaled.
  • This gas is produced by the incomplete combustion of fossil fuels such as coal, natural gas, and gasoline.
  • Its chemical structure consists of a triple bond between the carbon and oxygen atoms, making it a very stable molecule.
  • Applications: Carbon Monoxide is used in various industrial processes such as the production of methanol and as a reducing agent in metallurgy.
  • Health Hazards: Prolonged exposure to Carbon Monoxide can lead to carbon monoxide poisoning, which can be fatal due to its ability to bind with hemoglobin and prevent oxygen transport in the blood.

 Additional Information

  • CO3
  • CO3 does not exist as a stable compound. It is often mistaken for the carbonate ion (CO₃²⁻), which is a polyatomic ion composed of one carbon atom bonded to three oxygen atoms and carries a negative charge.
  • The carbonate ion is common in compounds such as calcium carbonate (CaCO₃), which is found in limestone and chalk.
  • CO2
  • CO2, or Carbon Dioxide, is another molecular compound of carbon and oxygen, consisting of one carbon atom double-bonded to two oxygen atoms.
  • It is a naturally occurring gas in the Earth's atmosphere and is produced during respiration, combustion, and volcanic activity.
  • Applications: Carbon Dioxide is widely used in industries for carbonated beverages, fire extinguishers, and as a refrigerant.
  • C2O
  • C2O does not represent a commonly known or stable molecule. It may be a misrepresentation or an incorrect formula.

Question 71

If a sum of money doubles itself in 10 years on compound interest, then in how many more years will it become 16 times of itself at the same rate of interest?

  1. AOption (a)

    40

  2. BOption (b)

    20

  3. COption (c)

    10

  4. DOption (d)

    30

View answer & explanation

Correct answer

Answer: (d)D.

30

Why this answer is correct

Shortcut Trick

Let the sum of money become 2n times in n × T years, where T is the time to double.

Here, the sum doubles in 10 years, so T = 10 years.

We need the sum to become 16 times, and 16 = 24.

Total time for 16 times = 4 × 10 = 40 years.

Additional years required = 40 − 10 = 30 years.

∴ The correct answer is 30 years.

Alternate Method

Given:

Time to double (P → 2P) = 10 years

Target amount = 16 times (16P)

Calculations:

⇒ Amount (A) = P(1 + r/100)n

⇒ For doubling: 2P = P(1 + r/100)10 ⇒ 2 = (1 + r/100)10

⇒ For 16 times: 16P = P(1 + r/100)T ⇒ 16 = (1 + r/100)T

⇒ (2)4 = [(1 + r/100)10]4

⇒ (1 + r/100)T = (1 + r/100)40

⇒ Total time (T) = 40 years

⇒ More years needed = Total time − Initial time = 40 − 10 = 30 years

∴ The correct answer is 30 years.

Additional Information

Compound Interest Growth

In Compound Interest, if a sum becomes x times in t years, it will become xn times in n × t years.

Simple Interest vs CI Growth

In Simple Interest, if a sum doubles (becomes 2P) in 10 years, it means it adds P interest every 10 years. To become 16P, it needs 15P interest, taking 15 × 10 = 150 years.

Question 72

Nine men went to a restaurant. Eight of them spent Rs. 3 each on their meals and the ninth spent Rs. 2 more than the average expenditure of all the nine. Determine the total money spent by them. 

  1. AOption (a)

    Rs. 35

  2. BOption (b)

    Rs.32

  3. COption (c)

    Rs. 30.25

  4. DOption (d)

    Rs. 29.25

View answer & explanation

Correct answer

Answer: (d)D.

Rs. 29.25

Why this answer is correct

Shortcut Trick

Let the average expenditure of all 9 men be x.

The 9th man spent the average plus ₹2 (x + 2). This extra ₹2 is distributed among the other 8 men.

Extra per person for 8 men = 2 ÷ 8 = ₹0.25.

Average (x) = Individual spend of 8 men + Extra share = 3 + 0.25 = ₹3.25.

Total Expenditure = Average × Number of men = 3.25 × 9 = ₹29.25.

∴ The correct answer is ₹29.25.

Alternate Method

Given: Number of men = 9. Spending of 8 men = ₹3 each. 9th man spent ₹2 more than the total average.

Formula Used: Total Expenditure = Average × Number of items.

⇒ Let the average expenditure be x.

⇒ Total expenditure = 9 × x = 9x.

⇒ Total expenditure = (8 × 3) + (x + 2).

⇒ 9x = 24 + x + 2.

⇒ 9x − x = 26.

⇒ 8x = 26.

⇒ x = 26 ÷ 8 = 3.25.

⇒ Total money spent = 9 × 3.25 = ₹29.25.

∴ The correct answer is ₹29.25.

Additional Information

Average Concept

Average is the sum of all observations divided by the total number of observations. Formula: Average = Sum ÷ Count.

Deviation Method

In problems where one person spends more than the average, that extra amount is equally contributed to the remaining members to find the true average.

Weighted Average

When groups have different averages, the combined average is (n1x1 + n2x2) ÷ (n1 + n2).

Question 73

A negative sign in magnification of spherical mirrors indicates that the _______.

  1. AOption (a)

    image is diminished 

  2. BOption (b)

    image is enlarged 

  3. COption (c)

    image is virtual 

  4. DOption (d)

    image is real 

View answer & explanation

Correct answer

Answer: (d)D.

image is real 

Why this answer is correct

The Correct answer is image is real.

Key Points

  • The negative sign in the magnification of spherical mirrors indicates that the image formed is inverted.
  • In the case of mirrors, an inverted image is always a real image.
  • A real image is formed when the reflected rays actually meet at a point.
  • Convex mirrors always produce virtual, erect, and diminished images, but concave mirrors can produce real or virtual images depending on the object’s position.
  • When the object is placed beyond the focal point of a concave mirror, the image formed is real and inverted, leading to a negative magnification.
  • The magnification formula is: m = -v/u, where v is the image distance, u is the object distance, and the negative sign denotes the inverted (real) image.
  • This concept is crucial in applications such as optical instruments, telescopes, and projectors, which utilize real images.

 Additional Information

  • Image is diminished
  • A diminished image is smaller than the object.
  • It is typically formed by convex mirrors and some specific cases of concave mirrors.
  • Diminished images are usually virtual, although real images can also be diminished in specific setups.
  • Image is enlarged
  • An enlarged image is larger than the object.
  • It is often formed by a concave mirror when the object is placed between the focal point and the mirror.
  • Such images are usually virtual, although real images can also be enlarged in particular cases.
  • Image is virtual
  • A virtual image is formed when the reflected rays do not actually meet but appear to meet when extended backward.
  • Virtual images are always erect and are commonly produced by plane mirrors, convex mirrors, and concave mirrors under specific conditions.
  • Virtual images cannot be projected onto a screen.

Question 74

How many seats did the Indian National Congress win in Rajasthan in Lok Sabha election 2024?

  1. AOption (a)

    25

  2. BOption (b)

    1

  3. COption (c)

    14

  4. DOption (d)

    8

View answer & explanation

Correct answer

Answer: (d)D.

8

Why this answer is correct

The Correct answer is 8.

Key Points

  • In the 2024 Lok Sabha elections, the Indian National Congress secured 8 seats in Rajasthan.
  • Rajasthan has a total of 25 Lok Sabha constituencies, making it a significant state in national elections.
  • The Congress party's performance in Rajasthan reflects its ability to maintain a foothold in this politically diverse state despite electoral challenges.
  • Rajasthan has historically alternated between the two major political parties, Indian National Congress and Bharatiya Janata Party (BJP), in Lok Sabha elections.
  • The Congress party's campaign in Rajasthan focused on issues such as farmer welfare, unemployment, and social justice to resonate with the voters.
  • Rajasthan is known for its political dynamics, where factors like caste equations, rural-urban divide, and regional issues play a crucial role in determining electoral outcomes.
  • The Congress party's performance in Rajasthan was part of a broader strategy to reclaim its influence in northern India.

Question 75

A, B, E, F, P, Q and R are sitting around a circular table facing the centre. A sits fourth to the right of F. Only two people sit between A and Q. Only two people sit between R and Q. P sits to the immediate left of B. How many people sit between P and E when counted from the right of E? 

  1. AOption (a)

    Four

  2. BOption (b)

    Three

  3. COption (c)

    Two

  4. DOption (d)

    One

View answer & explanation

Correct answer

Answer: (c)C.

Two

Why this answer is correct

Given: A, B, E, F, P, Q and R are sitting around a circular table facing the centre. 

1) A sits fourth to the right of F. 

2) Only two people sit between A and Q. 

3) Only two people sit between R and Q.

4) P sits to the immediate left of B.

After positioning B and P only one position is left which will be occupied by the only person left i.e. E.

Thus, according to the final arrangement, two people sit between P and E when counted from the right of E.

Hence, "Option 3" is the correct answer.

Question 76

Two numbers are respectively 20% and 25% more than a third number. What percentage of the second number is the first number?  

  1. AOption (a)

    80%

  2. BOption (b)

    125%

  3. COption (c)

    85%

  4. DOption (d)

    96%

View answer & explanation

Correct answer

Answer: (d)D.

96%

Why this answer is correct

Shortcut Trick

Let the third number be 100.

First number = 120 and Second number = 125.

Required percentage = (First number ÷ Second number) × 100.

⇒ (120 ÷ 125) × 100 = 24 × 4 = 96%.

∴ The correct answer is 96%.

Alternate Method

Given:

First number = 20% more than third number.

Second number = 25% more than third number.

Formula Used:

Percentage = (Value ÷ Base Value) × 100

Calculations:

Let the third number be x.

⇒ First number = x + 20% of x = 1.20x

⇒ Second number = x + 25% of x = 1.25x

⇒ Required Percentage = (1.20x ÷ 1.25x) × 100

⇒ Required Percentage = (120 ÷ 125) × 100

⇒ Required Percentage = 0.96 × 100 = 96%

∴ The correct answer is 96%.

Additional Information

Base Change Rule

Always identify the value after the word 'than' or 'of' as the base (denominator) for percentage calculations.

Percentage Increase

If a number is increased by R%, the new number is (100 + R)/100 × original number.

Fraction to Percentage Conversion

4/5 = 80%, 24/25 = 96%, 1/4 = 25%. Knowing these common fractions helps in fast calculation.

Question 77

Seven boxes, A, B, E, F, L, M and P, are kept one over the other but not necessarily in the same order. Only A is kept above E. Only two boxes are kept between E and F. Only P is kept below M. B is not kept immediately above F. Which box is kept second above L? 

  1. AOption (a)

    E

  2. BOption (b)

    F

  3. COption (c)

    B

  4. DOption (d)

    A

View answer & explanation

Correct answer

Answer: (a)A.

E

Why this answer is correct

Given: Seven boxes, A, B, E, F, L, M and P, are kept one over.

1) Only A is kept above E. 

2) Only P is kept below M.

Sr.noBoxes
Top
1A
2E
3
4
5
6M
7P
Bottom

3) Only two boxes are kept between E and F.

Sr.noBoxes
Top
1A
2E
3
4
5F
6M
7P
Bottom

4) B is not kept immediately above F.

After positioning B only one position is left which will be occupied by the only person left i.e. L.

Sr.noBoxes
Top
1A
2E
3B
4L
5F
6M
7P
Bottom

Thus, according to the final arrangement E box is kept second above L.

Hence, "Option 1" is the correct answer.

Question 78

The ovule develops and gets converted into which of the following after fertilisation?  

  1. AOption (a)

    Anther 

  2. BOption (b)

    Fruit 

  3. COption (c)

    Seed 

  4. DOption (d)

    Sepal  

View answer & explanation

Correct answer

Answer: (c)C.

Seed 

Why this answer is correct

The Correct answer is Seed.

Key Points

  • After fertilisation in plants, the ovule undergoes significant changes and develops into a seed.
  • The zygote formed during fertilisation develops into the embryo, which is the essential part of the seed.
  • The outer layers of the ovule harden to form the seed coat, which protects the developing embryo inside.
  • The seed also contains the endosperm (in some plants), which serves as a source of nutrients for the growing embryo.
  • Seeds are responsible for reproduction and dispersal in plants, enabling them to propagate across different regions.
  • The seed contains genetic material that ensures the growth of a plant identical to its parent, maintaining the species' continuity.
  • Seeds can remain dormant for long periods under suitable conditions, waiting for favorable environmental factors to germinate.
  • Examples of plants that produce seeds include mango, wheat, rice, and sunflower.

 Additional Information

  • Anther
  • The anther is a part of the male reproductive organ in plants, located in the stamen.
  • It produces and releases pollen grains, which are essential for fertilisation.
  • The anther is not involved in the development of the ovule or seed.
  • Fruit
  • The fruit is formed from the ovary of the flower after fertilisation.
  • It serves as a protective covering for seeds and aids in their dispersal.
  • Examples of fruits include apple, mango, and orange.
  • Sepal
  • The sepal is a part of the flower that protects the bud before it blooms.
  • Sepals are typically green and do not develop into seeds or fruits.

Question 79

If the volume of a cube is 512 cm3, then the measure of the main diagonal of the cube will be

  1. AOption (a)

    7√3 cm

  2. BOption (b)

    17√3 cm

  3. COption (c)

    14√3 cm

  4. DOption (d)

    8√3 cm

View answer & explanation

Correct answer

Answer: (d)D.

8√3 cm

Why this answer is correct

Shortcut Trick

Volume of cube = a3 = 512 ⇒ side (a) = 8 cm.

Main diagonal of a cube = a√3.

Diagonal = 8 × √3 = 8√3 cm.

∴ The correct answer is 8√3 cm.

Alternate Method

Given: Volume of the cube = 512 cm3.

Formula Used: Volume = a3 and Main Diagonal = a√3, where a is the edge of the cube.

Calculations:

⇒ a3 = 512

⇒ a = 3√512

⇒ a = 8 cm

⇒ Main Diagonal = a × √3

⇒ Main Diagonal = 8√3 cm

∴ The correct answer is 8√3 cm.

Additional Information

Total Surface Area of Cube

The Total Surface Area (TSA) of a cube is calculated as 6 × a2, representing the area of all 6 square faces.

Face Diagonal of Cube

The Face Diagonal of a cube is the diagonal of any single square face, given by the formula a√2.

Volume of a Cuboid

For a cuboid with dimensions length (l), width (w), and height (h), the Volume is l × w × h and the Diagonal is √(l2 + w2 + h2).

Question 80

Study the table given below and answer the question. The table shows the sale and profits of Company X. 

YearSale (in cr)Profits (in cr)
2019202
2020254
2021306
2022326.5
2023347
<br>

What were the profits as a percentage of sale in 2021?

  1. AOption (a)

    15%

  2. BOption (b)

    20%

  3. COption (c)

    25%

  4. DOption (d)

    10%

View answer & explanation

Correct answer

Answer: (b)B.

20%

Why this answer is correct

Given:

Sale in 2021 = ₹30 cr

Profits in 2021 = ₹6 cr

Formula used:

Profits as a percentage of Sale = (Profits / Sale) × 100

Calculation:

Profits as a percentage of Sale = (6 / 30) × 100

⇒ Profits as a percentage of Sale = 0.2 × 100

⇒ Profits as a percentage of Sale = 20%

∴ The correct answer is option 2.

Question 81

The sum of the first five prime numbers is: 

  1. AOption (a)

    29

  2. BOption (b)

    26

  3. COption (c)

    27

  4. DOption (d)

    28

View answer & explanation

Correct answer

Answer: (d)D.

28

Why this answer is correct

Shortcut Trick

List the first five prime numbers starting from 2.

The numbers are: 2, 3, 5, 7, 11.

Sum = 2 + 3 + 5 + 7 + 11 = 28.

∴ The correct answer is 28.

Alternate Method

Given: First five prime numbers.

Formula Used: Sum = n1 + n2 + n3 + n4 + n5

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

⇒ 1st prime number = 2 (the only even prime)

⇒ 2nd prime number = 3

⇒ 3rd prime number = 5

⇒ 4th prime number = 7

⇒ 5th prime number = 11

⇒ Sum = 2 + 3 + 5 + 7 + 11

⇒ Sum = 28

∴ The correct answer is 28.

Additional Information

Prime Numbers Properties

The number 2 is the smallest and only even prime number. All other prime numbers are odd.

Composite Numbers

Numbers with more than two factors are called composite numbers. Note that 1 is neither prime nor composite.

Twin Primes

Pairs of prime numbers with a difference of 2 are called twin primes (e.g., 3 and 5, 5 and 7, 11 and 13).

Question 82

Find the magnitude of applied force on a box of mass 10 kg for 20 s. It increases the box's velocity from 5 m s-1 to 15 m s-1?.

  1. AOption (a)

    1 N

  2. BOption (b)

    4 N

  3. COption (c)

    5 N

  4. DOption (d)

    10 N

View answer & explanation

Correct answer

Answer: (c)C.

5 N

Why this answer is correct

The Correct answer is 5 N.

Key Points

  • The formula to calculate the force is derived from Newton's second law of motion: F = ma, where F is the force, m is the mass of the object, and a is the acceleration.
  • Here, the mass of the box is given as 10 kg.
  • To find acceleration, we use the formula: a = (v - u)/t, where:
  • v = final velocity = 15 m/s
  • u = initial velocity = 5 m/s
  • t = time = 20 s
  • Substituting the values:
  • a = (15 - 5)/20 = 10/20 = 0.5 m/s²
  • Now, substituting m = 10 kg and a = 0.5 m/s² into the formula F = ma:
  • F = 10 × 0.5 = 5 N
  • Thus, the magnitude of the applied force is 5 N.

 Additional Information

  • Key Concepts in the Question
  • Newton's second law: It relates force, mass, and acceleration. The force acting on an object is equal to the product of its mass and acceleration.
  • Acceleration: It is the rate of change of velocity with respect to time and is calculated using the formula a = (v - u)/t.
  • Mass: The mass of the object is an essential factor in determining the force required to change its velocity.
  • SI Units: The standard units used in the calculation are:
  • Force (F): Newton (N)
  • Mass (m): Kilograms (kg)
  • Acceleration (a): Meters per second squared (m/s²)

Question 83

Match the hormones with their respective functions. 

HormonesFunctions
1.Thyroxina.Control body’s growth and development
2.Growth hormoneb.Male sex organ development
3.Testosteronec.Controls the level of blood sugar in the body
4.Insulind.Controls the body's metabolism of fat, protein and carbohydrates.
  1. AOption (a)

    1 - b, 2 - a, 3 - d, 4 - c

  2. BOption (b)

    1 - a, 2 - c, 3 - b, 4 - d

  3. COption (c)

    1 - d, 2 - a, 3 - b, 4 - c

  4. DOption (d)

    1 - d, 2 - b, 3 - c, 4 - a

View answer & explanation

Correct answer

Answer: (c)C.

1 - d, 2 - a, 3 - b, 4 - c

Why this answer is correct

The Correct answer is Option 3.

Key Points

  • Thyroxin controls the body's metabolism, including the metabolism of fat, protein, and carbohydrates. This hormone is secreted by the thyroid gland.
  • Growth hormone, secreted by the pituitary gland, is responsible for controlling the body's growth and development. It stimulates cell growth and regeneration.
  • Testosterone is a male sex hormone responsible for the development of male sex organs and secondary sexual characteristics such as facial hair and deepened voice.
  • Insulin is secreted by the pancreas and plays a crucial role in regulating the level of blood sugar in the body. It helps cells absorb glucose from the blood.

 Additional Information

  • Thyroxin
  • Thyroxin is produced by the thyroid gland located in the neck.
  • This hormone plays an essential role in maintaining the body's basal metabolic rate (BMR).
  • A deficiency of thyroxin may lead to hypothyroidism, while excess production may cause hyperthyroidism.
  • Growth Hormone
  • Growth hormone is secreted by the anterior pituitary gland.
  • Deficiency in growth hormone may lead to dwarfism, while its excess can cause gigantism.
  • Testosterone
  • Testosterone is produced by the testes in males.
  • This hormone also plays a role in promoting muscle mass and bone density.
  • In females, a small amount of testosterone is produced by the adrenal glands.
  • Insulin
  • Insulin is crucial for the metabolism of glucose in the body.
  • A deficiency of insulin can lead to diabetes mellitus, a condition characterized by high blood sugar levels.
  • Insulin was first discovered by Frederick Banting and Charles Best in 1921.

Question 84

Which of the following options should come in place of the question mark (?) in the given series based on the English alphabetical order?

GKF JNI MQL PTO ?

  1. AOption (a)

    SRW

  2. BOption (b)

    SWR

  3. COption (c)

    WSR

  4. DOption (d)

    WRS

View answer & explanation

Correct answer

Answer: (b)B.

SWR

Why this answer is correct

The logic followed here is:

​

Hence, "Option 2" is the correct answer.

Question 85

In a certain code language, 

‘P + Q’ means ‘P is the mother of Q’,

‘P - Q’ means ‘P is the wife of Q’,

‘P × Q’ means ‘P is the father of Q’ and

‘P ÷ Q’ means ‘P is the brother of Q’.

How is A related to E if ‘A + B - C × D ÷ E'?

  1. AOption (a)

    Father’s sister

  2. BOption (b)

    Mother’s sister 

  3. COption (c)

    Mother’s mother 

  4. DOption (d)

    Father’s mother 

View answer & explanation

Correct answer

Answer: (c)C.

Mother’s mother 

Why this answer is correct

Decoding symbols:

P is
Symbol+-×÷
MeaningMotherWifeFatherBrother
to Q

Given: A + B - C × D ÷ E

A + B → A is the mother of B.

B - C → B is the wife of C.

C × D → C is the father of D.

D ÷ E → D is the brother of E.

Thus, A is E's mother's mother or maternal grandmother.

Hence, the correct answer is "Option 3".

Question 86

Which of the following is produced when carbon dioxide reacts with calcium hydroxide? 

  1. AOption (a)

    CaO + H2O

  2. BOption (b)

    CaCO3 + H2O

  3. COption (c)

    CO + H2O

  4. DOption (d)

    H2CO3 + H2O

View answer & explanation

Correct answer

Answer: (b)B.

CaCO3 + H2O

Why this answer is correct

The Correct answer is CaCO3 + H2O.

Key Points

  • When carbon dioxide reacts with calcium hydroxide (slaked lime), the reaction produces calcium carbonate (CaCO3) and water (H2O).
  • This reaction is represented by the chemical equation: CO2 + Ca(OH)2 → CaCO3 + H2O.
  • Calcium carbonate (CaCO3) is a white precipitate that is insoluble in water, which is why the reaction is often used to test for the presence of carbon dioxide gas.
  • This reaction has practical applications in processes like limewater tests for detecting carbon dioxide and in the building industry for producing materials like cement and mortar.
  • Limewater, a dilute solution of calcium hydroxide, turns milky upon exposure to carbon dioxide due to the formation of calcium carbonate.
  • The reaction is an example of an acid-base reaction, where carbon dioxide (a weak acid) reacts with calcium hydroxide (a base).

 Additional Information

  • CaO + H2O
  • This reaction represents the combination of calcium oxide (quicklime) with water to form calcium hydroxide (slaked lime).
  • The equation for this reaction is: CaO + H2O → Ca(OH)2.
  • It is an exothermic reaction, releasing a large amount of heat.
  • This process is widely used in the construction industry for making lime mortar and in agriculture to reduce soil acidity.
  • CO + H2O
  • Carbon monoxide (CO) does not react with water under normal conditions to produce a stable product.
  • However, in industrial processes like the water-gas shift reaction, CO reacts with steam (H2O) in the presence of a catalyst to produce hydrogen gas (H2) and carbon dioxide (CO2).
  • The equation for this reaction is: CO + H2O → CO2 + H2.
  • This reaction is significant in the production of hydrogen gas for use in fuel cells and ammonia synthesis.
  • H2CO3 + H2O
  • Carbonic acid (H2CO3) is formed when carbon dioxide dissolves in water: CO2 + H2O → H2CO3.
  • However, this compound is unstable and partially dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-).
  • This reaction is critical in maintaining the acid-base balance in the human body and is part of the carbon dioxide transport mechanism in blood.

Question 87

Based on the English alphabetical order, three of the following four letter-clusters are alike in a certain way and thus form a group. Which letter-cluster does not belong to that group?

(Note: The odd one out is not based on the number of consonants/vowels or their position in the letter-cluster.)

  1. AOption (a)

    QTO

  2. BOption (b)

    PSN

  3. COption (c)

    WZV

  4. DOption (d)

    UXS

View answer & explanation

Correct answer

Answer: (c)C.

WZV

Why this answer is correct

The logic followed here is:

Option 1) QTO

Option 2) PSN

Option 3) WZV

Option 4) UXS

Thus, out of all the options 'WZV' is the odd one out.

Hence, "Option 3" is the correct answer.

Question 88

The sum of three consecutive multiples of 9 is 2457, find the smallest one.

  1. AOption (a)

    810

  2. BOption (b)

    990

  3. COption (c)

    819

  4. DOption (d)

    999

View answer & explanation

Correct answer

Answer: (a)A.

810

Why this answer is correct

Shortcut Trick

Average of consecutive numbers is always the middle term.

Middle number = Total Sum ÷ Count ⇒ 2457 ÷ 3 = 819.

Since they are multiples of 9, the numbers are (819 − 9), 819, and (819 + 9).

Smallest number = 819 − 9 = 810.

∴ The correct answer is 810.

Alternate Method

Let the three consecutive multiples of 9 be (x − 9), x, and (x + 9).

Given: Sum of these numbers = 2457

⇒ (x − 9) + x + (x + 9) = 2457

⇒ 3x = 2457

⇒ x = 2457 ÷ 3

⇒ x = 819

⇒ Smallest number = x − 9 = 819 − 9 = 810

∴ The correct answer is 810.

Additional Information

Arithmetic Progression (AP)

Consecutive multiples of any number 'n' always form an Arithmetic Progression with common difference 'd' = n.

Middle Term Property

For an odd number of terms in AP, the Average (Sum ÷ Count) is always equal to the middle term of the series.

Multiple Check

A number is a multiple of 9 if the sum of its digits is divisible by 9. For 810, 8 + 1 + 0 = 9, which is divisible by 9.

Question 89

Nutrition is provided to the embryo from the mother’s blood with the help of the: 

  1. AOption (a)

    oviduct 

  2. BOption (b)

    placenta 

  3. COption (c)

    scrotum 

  4. DOption (d)

    ovary 

View answer & explanation

Correct answer

Answer: (b)B.

placenta 

Why this answer is correct

The Correct answer is placenta.

Key Points

  • The placenta is a specialized structure that forms between the mother and the developing embryo during pregnancy in mammals.
  • It facilitates the exchange of nutrients, oxygen, and waste products between the mother’s blood and the embryo's blood.
  • The placenta is connected to the embryo via the umbilical cord, which acts as a lifeline for the developing fetus.
  • It allows essential nutrients such as glucose, amino acids, and vitamins to pass from the mother’s bloodstream to the fetus.
  • The placenta also removes waste products like carbon dioxide and urea produced by the embryo and transfers them to the mother's blood for excretion.
  • It acts as a protective barrier, preventing certain harmful substances, like many bacteria, from reaching the fetus, though some drugs and viruses can pass through.
  • Additionally, the placenta produces important hormones such as progesterone and human chorionic gonadotropin (hCG), which are crucial for maintaining pregnancy.
  • The placenta begins to form shortly after implantation of the embryo and is fully functional by the 12th week of pregnancy.

 Additional Information

  • Oviduct
  • The oviduct, also known as the fallopian tube, is a part of the female reproductive system.
  • Its primary function is to transport the egg from the ovary to the uterus.
  • Fertilization of the egg by the sperm typically occurs in the oviduct.
  • It does not play a role in providing nutrition to the embryo.
  • Scrotum
  • The scrotum is a pouch of skin containing the testes in males.
  • It helps maintain the optimum temperature for sperm production, which is slightly lower than the body temperature.
  • It is not involved in the development or nutrition of the embryo.
  • Ovary
  • The ovary is the female reproductive organ responsible for producing eggs (ova) and secreting hormones such as estrogen and progesterone.
  • While the ovary releases the egg for fertilization, it does not provide nutrition to the embryo.

Question 90

A dealer buys three varieties of apples at Rs. 50, Rs. 40 and Rs. 30 per kilogram respectively. He mixes them in the ratio 2 : 4 : 9 respectively. by weight, and sells them at a profit of 30%. At what approximate price (per kilogram) does he sell the mixed variety of apples?

  1. AOption (a)

    Rs. 23.50

  2. BOption (b)

    Rs. 75.00

  3. COption (c)

    Rs. 10.80

  4. DOption (d)

    Rs. 45.90

View answer & explanation

Correct answer

Answer: (d)D.

Rs. 45.90

Why this answer is correct

Shortcut Trick

Ratio of weights = 2 : 4 : 9. Total weight = 2 + 4 + 9 = 15 kg.

Weighted average CP = (2 × 50 + 4 × 40 + 9 × 30) ÷ 15 = (100 + 160 + 270) ÷ 15 = 530 ÷ 15 = Rs. 35.33.

SP = Average CP × (100 + P%) ÷ 100 = 35.33 × 1.30 = Rs. 45.93.

Approximate Selling Price is Rs. 45.90.

∴ The correct answer is Rs. 45.90.

Alternate Method

Given → CP1 = Rs. 50, CP2 = Rs. 40, CP3 = Rs. 30 | Ratio = 2 : 4 : 9 | Profit = 30%. Formulas: Average CP = Total CP ÷ Total Weight | SP = CP × (100 + Profit%) ÷ 100.

⇒ Total Cost Price = (2 × 50) + (4 × 40) + (9 × 30) = 100 + 160 + 270 = Rs. 530. ⇒ Total Weight = 2 + 4 + 9 = 15 kg. ⇒ Cost Price per kg = 530 ÷ 15 = Rs. 35.333. ⇒ Selling Price per kg = 35.333 × (130 ÷ 100) = 35.333 × 1.3 = Rs. 45.933. ⇒ The closest approximate value from options is Rs. 45.90.

∴ The correct answer is Rs. 45.90.

Additional Information

Weighted Average Cost Price

When items of different costs are mixed, the average cost is calculated as (Sum of Price × Quantity) ÷ (Total Quantity).

Profit Calculation

Selling Price (SP) is always calculated on the Cost Price (CP) using the formula: SP = CP × (1 + Profit/100).

Question 91

D, E, F, G, L, M and N are sitting around a circular table facing the centre. Only one person sits between F and G when counted from the right of F. Only one person sits between G and D when counted from right of G. Only one person sits between F and L when counted from left of F. Only two people sit between E and D when counted from left of D. Only one person sits between N and L when counted from right of N. Who sits to the immediate right and left of M, respectively?

  1. AOption (a)

    D and E

  2. BOption (b)

    E and N

  3. COption (c)

    N and E

  4. DOption (d)

    F and L

View answer & explanation

Correct answer

Answer: (d)D.

F and L

Why this answer is correct

Given: D, E, F, G, L, M and N are sitting around a circular table facing the centre.

1) Only one person sits between F and G when counted from the right of F. 

2) Only one person sits between G and D when counted from right of G.

3) Only one person sits between F and L when counted from left of F. 

4) Only two people sit between E and D when counted from left of D. 

5) Only one person sits between N and L when counted from right of N. 

After positioning N only one position is left which will be occupied by the only person left i.e. M.

Thus, according to the final arrangement, F and L sits to the immediate right and left of M, respectively.

Hence, "Option 4" is the correct answer.

Question 92

The smallest ratio out of 1 : 1, 2 : 1, 1 : 3 and 3 : 1 is:

  1. AOption (a)

    3 : 1

  2. BOption (b)

    1 : 3

  3. COption (c)

    2 : 1

  4. DOption (d)

    1 : 1

View answer & explanation

Correct answer

Answer: (b)B.

1 : 3

Why this answer is correct

Shortcut Trick Convert all ratios to decimal form by dividing the first term by the second term. 1 : 1 = 1.0 2 : 1 = 2.0 1 : 3 = 0.33 3 : 1 = 3.0 Comparing the values, 0.33 is the minimum value. ∴ The correct answer is 1 : 3. Alternate Method Given: Ratios are 1 : 1, 2 : 1, 1 : 3, and 3 : 1. Formula Used: Ratio a : b can be written as the fraction a/b.

⇒ Expressing ratios as fractions: 1/1, 2/1, 1/3, 3/1 ⇒ To compare, make the denominators equal. The LCM of (1, 1, 3, 1) is 3. ⇒ 1/1 = 3/3 ⇒ 2/1 = 6/3 ⇒ 1/3 = 1/3 ⇒ 3/1 = 9/3 ⇒ Comparing numerators (3, 6, 1, 9), the smallest numerator is 1. ⇒ Therefore, 1/3 is the smallest fraction. ∴ The correct answer is 1 : 3. Additional Information Comparison of Ratios Two ratios a : b and c : d are compared by converting them to like fractions or by checking the value of ad and bc. If ad < bc, then a : b < c : d. Compound Ratio The compound ratio of (a : b) and (c : d) is (ac : bd). It is found by multiplying the corresponding antecedents and consequents. Inverse Ratio The inverse ratio of a : b is b : a. For example, the inverse of 1 : 3 is 3 : 1.

Question 93

YTXS is related to QLPK in a certain way based on the English alphabetical order. In the same way, UPTO is related to MHLG. To which of the following options is RMQL related, following the same logic?

  1. AOption (a)

    EJDI

  2. BOption (b)

    EJID

  3. COption (c)

    JEID

  4. DOption (d)

    JEDI

View answer & explanation

Correct answer

Answer: (c)C.

JEID

Why this answer is correct

The logic followed here is:

YTXS is related to QLPK

And,

UPTO is related to MHLG

Similarly,

RMQL is related to

Hence, "Option 3" is the correct answer.

Question 94

Methane, on burning with oxygen, gives which of the following products?

  1. AOption (a)

    Carbon dioxide and water

  2. BOption (b)

    Carbonic acid

  3. COption (c)

    Carbon monoxide and water

  4. DOption (d)

    Carbon monoxide only

View answer & explanation

Correct answer

Answer: (a)A.

Carbon dioxide and water

Why this answer is correct

The correct answer is Carbon dioxide and water.

Key Points

  • Methane (CH4) is a simple hydrocarbon and the main component of natural gas.
  • When methane burns in the presence of sufficient oxygen, it undergoes complete combustion.
  • The chemical reaction for complete combustion of methane is: CH4 + 2O2 → CO2 + 2H2O.
  • This reaction produces carbon dioxide (CO2) and water vapor (H2O) as the primary products.
  • Complete combustion releases a large amount of energy, making methane an efficient fuel.
  • Carbon dioxide and water produced are gases at standard temperature and pressure, with water mostly in vapor form due to the heat of combustion.
  • In the absence of sufficient oxygen, incomplete combustion may occur, producing carbon monoxide (CO) and soot, but this is not the typical reaction when methane burns properly.
  • Methane combustion is widely used for heating, cooking, and electricity generation.

 Additional Information

  • Carbonic Acid
  • Carbonic acid (H2CO3) forms when carbon dioxide dissolves in water.
  • It is an intermediate in the carbon cycle but is not a direct product of methane combustion.
  • Carbonic acid plays a key role in ocean acidification but is unrelated to the burning of methane.
  • Carbon monoxide and water
  • Carbon monoxide (CO) is produced during incomplete combustion due to insufficient oxygen.
  • Incomplete combustion is hazardous because CO is a poisonous gas.
  • Complete combustion of methane ideally avoids producing CO.
  • Carbon monoxide only
  • Carbon monoxide is never the sole product of methane combustion.
  • It appears only in incomplete combustion scenarios along with other products like soot and water vapor.

Question 95

18 boys and 24 girls can complete a piece of work in 16 days. All of them started working together but after 12 working days, all girls and 6 boys stopped working. 12 boys completed the remaining work in 9 days. How many days will it take to complete the entire job if only 24 girls have to complete the job?

  1. AOption (a)

    48 days

  2. BOption (b)

    32 days

  3. COption (c)

    40 days

  4. DOption (d)

    24 days

View answer & explanation

Correct answer

Answer: (a)A.

48 days

Why this answer is correct

Shortcut Trick

Work done in 12 days by 18B + 24G = 12/16 = 3/4 of the total work.

Remaining work = 1 − 3/4 = 1/4 of total work.

12 boys take 9 days for 1/4 work → 12 boys take 36 days for full work → 1 boy efficiency = 1/(12 × 36) = 1/432.

Total work from initial condition: 16 × (18/432 + 24G) = 1 → 18/432 + 24G = 1/16 → 1/24 + 24G = 1/16 → 24G = 1/16 − 1/24 = 1/48.

24 girls efficiency = 1/48 per day → Time taken = 48 days.

∴ The correct answer is 48 days.

Alternate Method

Given: 18 Boys (B) and 24 Girls (G) work for 16 days. After 12 days, 12 Boys complete the rest in 9 days.

Formula Used: Total Work = Efficiency × Time

⇒ Total Work (W) = 16 × (18B + 24G)

⇒ Work done in 12 days = 12 × (18B + 24G)

⇒ Remaining work = (16 − 12) × (18B + 24G) = 4 × (18B + 24G)

⇒ Remaining work is completed by 12 boys in 9 days = 12B × 9 = 108B

⇒ 4 × (18B + 24G) = 108B

⇒ 72B + 96G = 108B

⇒ 96G = 36B → 8G = 3B → 1B = (8/3)G

⇒ Total Work = 16 × [18 × (8/3)G + 24G] = 16 × [48G + 24G] = 16 × 72G

⇒ Time for 24 girls = Total Work ÷ Efficiency of 24 girls

⇒ Time = (16 × 72G) ÷ 24G = 16 × 3 = 48 days

∴ The correct answer is 48 days.

Additional Information

Man-Days Concept

Total work is often expressed as the product of the number of workers and the days taken: W = M1 × D1 = M2 × D2.

Efficiency Ratio

If efficiencies are given as E1 and E2, then Work = (n1E1 + n2E2) × Days. This allows conversion between different worker types (e.g., boys to girls).

Remaining Work Rule

When workers leave, focus on the remaining portion of work: (Remaining Days × Original Team) = (New Days × New Team).

Question 96

An electric lamp, whose resistance is 10 Ω, and a conductor of 2 Ω resistance are connected to a 24 V battery in series. Then the current through the circuit will be ________.

  1. AOption (a)

    3 A

  2. BOption (b)

    2 A

  3. COption (c)

    1 A

  4. DOption (d)

    4 A

View answer & explanation

Correct answer

Answer: (b)B.

2 A

Why this answer is correct

The Correct answer is 2 A.

Key Points

  • The total resistance in the circuit can be calculated since the resistor values are in series.
  • For resistors connected in series, the total resistance is the sum of individual resistances.
  • Here, the resistance of the electric lamp is 10 Ω, and the conductor has a resistance of 2 Ω.
  • Total resistance, R = 10 Ω + 2 Ω = 12 Ω.
  • The voltage of the battery is given as 24 V.
  • Using Ohm’s Law (V = IR), the current through the circuit can be calculated:
  • I = V / R
  • Substituting the values, I = 24 V / 12 Ω = 2 A.
  • Thus, the current flowing through the circuit is 2 A.
  • This is why the correct answer is 2 A.

 Additional Information

  • Ohm's Law:
  • It states that the current (I) flowing through a conductor is directly proportional to the voltage (V) across its ends, provided the temperature and other physical conditions remain constant.
  • The formula is expressed as V = IR, where R is the resistance.
  • Series Circuit:
  • In a series circuit, the total resistance is the sum of all individual resistances.
  • The current remains the same through all components in a series circuit.
  • Applications of Ohm's Law:
  • Used in calculating resistance, current, or voltage in electrical circuits.
  • Helpful in designing electrical and electronic circuits.

Question 97

Which of the following options should come in place of the question mark (?) in the given series to make it logically complete?

HN18, KQ27, NT36, QW45, ?

  1. AOption (a)

    TZ54

  2. BOption (b)

    SY55

  3. COption (c)

    SY54

  4. DOption (d)

    TZ55

View answer & explanation

Correct answer

Answer: (a)A.

TZ54

Why this answer is correct

The logic followed here is:

Hence, "Option 1" is the correct answer.

Question 98

Due to decrease in manpower, the production in a factory decreases by 25%. By what percentage should the working hours be increased to restore the original production?

  1. AOption (a)

    50%

  2. BOption (b)

    4367%43\frac{6}{7}\%

  3. COption (c)

    3313%33\frac{1}{3}\%

  4. DOption (d)

    25%

View answer & explanation

Correct answer

Answer: (c)C.

3313%33\frac{1}{3}\%

Why this answer is correct

Shortcut Trick

Product = Manpower × Working Hours

Decrease in production = 25% = 1/4 → New production = 3/4 of original.

To restore original production, multiply by 4/3.

Required increase = (4 − 3) / 3 = 1/3 = 33(1/3)%

∴ The correct answer is 33(1/3)%.

Alternate Method

Given:

Original Production = 100 units

Decrease in Manpower leads to 25% decrease in Production.

⇒ New Production = 100 − 25 = 75 units

To restore production to 100, increase needed = 100 − 75 = 25 units

⇒ Percentage increase in Working Hours = (Increase / New Production) × 100

⇒ % Increase = (25 / 75) × 100

⇒ % Increase = (1 / 3) × 100 = 33(1/3)%

∴ The correct answer is 33(1/3)%.

Additional Information

Inverse Variation Principle

If a quantity is a product of two variables (A × B = Constant), then a decrease in A by x% requires an increase in B by [x / (100 − x)] × 100% to keep the product constant.

Fractional Conversion

Common fractions: 1/2 = 50%, 1/3 = 33(1/3)%, 1/4 = 25%, 1/5 = 20%, 1/6 = 16(2/3)%.

Question 99

The ratio of copper and zinc in the brass is 13 : 7. How much zinc will there be in 100 kg of brass? 

  1. AOption (a)

    70 kg 

  2. BOption (b)

    14 kg

  3. COption (c)

    35 kg

  4. DOption (d)

    42 kg

View answer & explanation

Correct answer

Answer: (c)C.

35 kg

Why this answer is correct

Shortcut Trick

Total ratio parts = 13 (Copper) + 7 (Zinc) = 20 units.

20 units corresponds to the total weight of Brass = 100 kg.

1 unit = 100 ÷ 20 = 5 kg.

Weight of Zinc = 7 units × 5 kg = 35 kg.

∴ The correct answer is 35 kg.

Alternate Method

Given:

Ratio of Copper to Zinc = 13 : 7

Total weight of Brass = 100 kg

Formula Used:

Quantity of a component = (Ratio of component ÷ Sum of ratios) × Total quantity

Calculations:

⇒ Sum of ratio parts = 13 + 7 = 20

⇒ Quantity of Zinc = (7 ÷ 20) × 100

⇒ Quantity of Zinc = 7 × 5

⇒ Quantity of Zinc = 35 kg

∴ The correct answer is 35 kg.

Additional Information

Ratio and Proportion

If a total quantity Q is divided in ratio a:b, the parts are [a/(a+b)] × Q and [b/(a+b)] × Q.

Alloys

Brass is an alloy primarily consisting of Copper and Zinc. The sum of the individual weights of the metals equals the total weight of the alloy.

Percentage Composition

To find the percentage of Zinc: (7 / 20) × 100 = 35%.

Question 100

Which of the following options should come in place of the question mark (?) in the given series to make it logically complete?  

19, 26, 33, 40, 47, ?

  1. AOption (a)

    52

  2. BOption (b)

    54

  3. COption (c)

    53

  4. DOption (d)

    51

View answer & explanation

Correct answer

Answer: (b)B.

54

Why this answer is correct

The logic followed here is:

Hence, "Option 2" is the correct answer.

100 questions in the full paper