Previous Year Paper

RRB Technician Grade III Official Paper (Held On: 29 Dec, 2024 Shift 1) (Previous Year Paper)

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Full Test (100 questions)

Question 1

Which of the following methods is used for refining impure metals? 

  1. AOption (a)

    Electrolytic refining 

  2. BOption (b)

    Painting 

  3. COption (c)

    Oiling 

  4. DOption (d)

    Galvanisation 

View answer & explanation

Correct answer

Answer: (a)A.

Electrolytic refining 

Why this answer is correct

The correct answer is Electrolytic refining.

Key Points

  • Electrolytic refining is a method used to purify impure metals by using electrolysis.
  • In this process, the impure metal is made the anode, and a pure metal strip is made the cathode.
  • An electrolyte solution containing the metal ions is used to facilitate the transfer of metal ions from the anode to the cathode.
  • As a result, the pure metal is deposited on the cathode, while impurities either fall off as anode mud or remain in the solution.
  • This method is commonly used for refining metals like copper, nickel, lead, and zinc.

Additional Information

  • Electrolysis is the process of using an electric current to drive a non-spontaneous chemical reaction.
  • In electrolytic refining, the energy supplied by the electric current helps in the separation of pure metal from its impurities.
  • Anode refers to the electrode where oxidation occurs, while the cathode refers to the electrode where reduction occurs.
  • Anode mud is the insoluble impurities that collect at the bottom of the electrolytic cell during the refining process.
  • This method ensures high purity levels of the refined metal, often exceeding 99.9% purity.

Question 2

If F1 force is required to accelerate an object of 5 kg mass at 10 m s-2 and F2 force to accelerate an object of 10 kg mass at 12 m s-2 , then which of the following statements is true?

  1. AOption (a)

    F1 > F2

  2. BOption (b)

    F1 = F2

  3. COption (c)

    F2 > F1

  4. DOption (d)

    F2 = -2 × F1

View answer & explanation

Correct answer

Answer: (c)C.

F2 > F1

Why this answer is correct

The correct answer is 3) F2 > F1.

Key Points

  • Force (F) is calculated using Newton's Second Law of Motion, which states that F = m × a, where m is mass and a is acceleration.
  • For F1: The force needed to accelerate a 5 kg object at 10 m/s² is calculated as F1 = 5 kg × 10 m/s² = 50 N.
  • For F2: The force needed to accelerate a 10 kg object at 12 m/s² is calculated as F2 = 10 kg × 12 m/s² = 120 N.
  • Comparing F1 and F2: 50 N < 120 N, hence F2 > F1.

Additional Information

  • Newton's Second Law of Motion: States that the force acting on an object is equal to the mass of that object multiplied by its acceleration (F = m × a).
  • SI Unit of Force: The SI unit of force is the Newton (N), which is defined as the force needed to accelerate a 1 kg mass by 1 m/s².
  • Mass: Mass is a measure of the amount of matter in an object and is usually measured in kilograms (kg).
  • Acceleration: Acceleration is the rate of change of velocity of an object and is measured in meters per second squared (m/s²).
  • Application: Understanding the relationship between force, mass, and acceleration is crucial in fields such as engineering, physics, and various applied sciences.

Question 3

Evaluate the given expression.  

(-18) + 6 ÷ 3 + 5

  1. AOption (a)

    11

  2. BOption (b)

    -11

  3. COption (c)

    1

  4. DOption (d)

    -1

View answer & explanation

Correct answer

Answer: (b)B.

-11

Why this answer is correct

Given:

(−18) + 6 ÷ 3 + 5

Formula used:

BODMAS Rule (Bracket, Of, Division, Multiplication, Addition, Subtraction)

Calculations:

(−18) + 6 ÷ 3 + 5

⇒ (−18) + 2 + 5

⇒ −18 + 7

⇒ −11

∴ The correct answer is option (2).

Question 4

The number of prime numbers lying between 400 and 430 is: 

  1. AOption (a)

    6

  2. BOption (b)

    4

  3. COption (c)

    5

  4. DOption (d)

    3

View answer & explanation

Correct answer

Answer: (b)B.

4

Why this answer is correct

Shortcut Trick

Identify numbers in the range 400 to 430 that are not divisible by 2, 3, 5, 7, 11, 13, 17, or 19.

Numbers to check: 401, 403, 407, 409, 413, 419, 421, 427, 429.

Eliminate: 403 (13×31), 407 (11×37), 413 (7×59), 427 (7×61), 429 (3×143).

Remaining Prime Numbers: 401, 409, 419, 421.

∴ The correct answer is 4.

Alternate Method

Given: Range of numbers between 400 and 430.

Method: To check if a number n is prime, test divisibility by all primes ≤ √n. Here, √430 ≈ 20.7, so test primes 2, 3, 5, 7, 11, 13, 17, 19.

⇒ 401: Not divisible by 2, 3, 5, 7, 11, 13, 17, 19 → Prime

⇒ 403: 13 × 31 = 403 → Not Prime

⇒ 407: 11 × 37 = 407 → Not Prime

⇒ 409: Not divisible by 2, 3, 5, 7, 11, 13, 17, 19 → Prime

⇒ 419: Not divisible by 2, 3, 5, 7, 11, 13, 17, 19 → Prime

⇒ 421: Not divisible by 2, 3, 5, 7, 11, 13, 17, 19 → Prime

⇒ List of primes: {401, 409, 419, 421}

⇒ Total count = 4

∴ The correct answer is 4.

Additional Information

Definition of Prime Numbers

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

Primality Test Rule

To check if N is prime, divide N by all prime numbers less than or equal to √N. If none divide N, then N is prime.

Twin Primes

Pairs of prime numbers that have a difference of 2 (e.g., 419 and 421 are twin primes).

Question 5

The value of [(10)150 ÷ (10)146] is

  1. AOption (a)

    1000

  2. BOption (b)

    105

  3. COption (c)

    10000

  4. DOption (d)

    106

View answer & explanation

Correct answer

Answer: (c)C.

10000

Why this answer is correct

Given:

(10)150 ÷ (10)146

Formula used:

am ÷ an = am−n

Calculations:

[(10)150 ÷ (10)146]

⇒ 10(150−146)

⇒ 104

⇒ 10 × 10 × 10 × 10

⇒ 10000

∴ The correct answer is option (3).

Question 6

Convex mirrors are fitted on the sides of vehicles because they always give ______.

  1. AOption (a)

    an erect and diminished image 

  2. BOption (b)

    a real image 

  3. COption (c)

    a narrower field of the view 

  4. DOption (d)

    an erect and an enlarged image 

View answer & explanation

Correct answer

Answer: (a)A.

an erect and diminished image 

Why this answer is correct

The correct answer is an erect and diminished image.

Key Points

  • Convex mirrors always produce an erect image irrespective of the distance of the object from the mirror.
  • The images formed by convex mirrors are always diminished, meaning they are smaller than the actual size of the object.
  • Convex mirrors provide a wider field of view compared to plane or concave mirrors, which is crucial for vehicle safety.
  • Due to these properties, convex mirrors are commonly used as rear-view mirrors in vehicles.
  • The positioning of convex mirrors helps drivers see a larger area behind them, thereby reducing blind spots.

Additional Information

  • Mirror Terminologies:
  • Focal point (F): The point where parallel rays of light either converge or appear to diverge after reflecting from the mirror.
  • Principal axis: The line passing through the center of curvature and the mirror's pole.
  • Center of curvature (C): The center of the sphere of which the mirror is a part.
  • Pole (P): The midpoint of the mirror's surface.
  • Types of Mirrors:
  • Plane mirrors: Produce virtual, erect, and same-sized images as the object.
  • Concave mirrors: Can produce real, inverted images or virtual, erect images depending on the object distance from the mirror.
  • Convex mirrors: Always produce virtual, erect, and diminished images.
  • Applications of Convex Mirrors:
  • Used in vehicle side mirrors for a wider field of view.
  • Employed in surveillance systems in stores and public places.
  • Utilized in road safety to give a view of oncoming traffic at blind curves and intersections.
  • Image Formation by Mirrors:
  • The nature, size, and orientation of the image formed depend on the type of mirror and the object's distance from the mirror.
  • Convex mirrors always form virtual images as they diverge light rays.

Question 7

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

27 ÷ 14 x 21 + 3 - 4 = ?

  1. AOption (a)

    13

  2. BOption (b)

    10

  3. COption (c)

    16

  4. DOption (d)

    15

View answer & explanation

Correct answer

Answer: (a)A.

13

Why this answer is correct

Given Equation: 

27 ÷ 14 x 21 + 3 - 4 = ?

BODMAS Rule:

After interchanging  ‘+' and ‘÷' and ‘x' and ‘-’, we get

27 + 14 - 21 ÷3 x 4 

⇒ 27 + 14 - 7 x 4 

⇒ 41 - 28 = 13 

Hence, the correct option is "Option 1".

Question 8

Which of the following is NOT a property of a colloid? 

  1. AOption (a)

    Colloids cannot be separated by filtration. 

  2. BOption (b)

    Colloid is a homogeneous mixture. 

  3. COption (c)

    Colloid is a heterogeneous mixture. 

  4. DOption (d)

    Particles of colloids do not settle down when left undisturbed. 

View answer & explanation

Correct answer

Answer: (b)B.

Colloid is a homogeneous mixture. 

Why this answer is correct

The correct answer is Colloid is a homogeneous mixture.

Key Points

  • Colloids are mixtures where one substance of microscopically dispersed insoluble particles is suspended throughout another substance.
  • Colloids cannot be separated by filtration due to the small size of the dispersed particles.
  • Colloids are heterogeneous mixtures because the composition is not uniform throughout.
  • Particles in a colloid do not settle down when left undisturbed because of their small size and constant motion caused by Brownian motion.

Additional Information

  • Brownian Motion:
  • The random movement of particles suspended in a fluid (liquid or gas) resulting from their collision with fast atoms or molecules in the gas or liquid.
  • Tyndall Effect:
  • The scattering of light by particles in a colloid or in a very fine suspension.
  • Types of Colloids:
  • Based on the state of the dispersed phase and the dispersion medium, colloids can be classified into various types like sols, gels, foams, and emulsions.
  • Examples of Colloids:
  • Milk (emulsion), fog (aerosol), and jelly (gel).

Question 9

The mean proportional between two numbers is given as the positive square root of the product of those two numbers. If 72 is the mean proportional between 18 and y, then the value of y is:  

  1. AOption (a)

    288

  2. BOption (b)

    488

  3. COption (c)

    388

  4. DOption (d)

    588

View answer & explanation

Correct answer

Answer: (a)A.

288

Why this answer is correct

Shortcut Trick

For Mean Proportional (MP) between 18 and y:

MP2 = 18 × y

⇒ 72 × 72 = 18 × y

⇒ y = (72 × 72) ÷ 18 = 4 × 72 = 288

∴ The correct answer is 288.

Alternate Method

Given:

First number = 18

Second number = y

Mean Proportional = 72

Formula Used:

Mean Proportional = √(a × b)

Calculations:

⇒ 72 = √(18 × y)

Squaring both sides:

⇒ 722 = 18 × y

⇒ 5184 = 18 × y

⇒ y = 5184 ÷ 18

⇒ y = 288

∴ The correct answer is 288.

Additional Information

Third Proportional

If a, b, and c are in continued proportion, then c is the third proportional where c = b2/a.

Fourth Proportional

For four numbers a, b, c, and d in proportion (a:b = c:d), d is the fourth proportional where d = (b × c)/a.

Continued Proportion

Three numbers a, b, c are in continued proportion if a/b = b/c, which implies b2 = ac.

Question 10

Express the speed of 25 m/s in km/h. 

  1. AOption (a)

    50 km/h

  2. BOption (b)

    99 km/h

  3. COption (c)

    15 km/h 

  4. DOption (d)

    90 km/h 

View answer & explanation

Correct answer

Answer: (d)D.

90 km/h 

Why this answer is correct

Shortcut Trick

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

Speed = 25 × (18/5) = 5 × 18 = 90 km/h.

∴ The correct answer is 90 km/h.

Alternate Method

Given:

Speed in m/s = 25 m/s

Formula Used:

Speed (km/h) = Speed (m/s) × (3600 / 1000)

Calculations:

⇒ 1 m = 1/1000 km

⇒ 1 sec = 1/3600 h

⇒ Speed = 25 × (1/1000) ÷ (1/3600)

⇒ Speed = 25 × (3600 / 1000)

⇒ Speed = 25 × (18 / 5)

⇒ Speed = 5 × 18

⇒ Speed = 90 km/h

∴ The correct answer is 90 km/h.

Additional Information

Speed Conversion Rules

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

Average Speed

Average Speed = Total Distance ÷ Total Time. For two equal distances with speeds x and y, Average Speed = 2xy/(x + y).

Relative Speed

Same direction: Subtract speeds (u − v). Opposite direction: Add speeds (u + v).

Question 11

A body of mass m and a body of mass 4m are dropped from the same height, the ratio of the time taken by the two bodies to reach the ground would be: (Air resistance is neglected) 

  1. AOption (a)

    4 : 1

  2. BOption (b)

    1 : 1

  3. COption (c)

    1 : 2

  4. DOption (d)

    1 : 4

View answer & explanation

Correct answer

Answer: (b)B.

1 : 1

Why this answer is correct

The correct answer is 1 : 1.

Key Points

  • In the absence of air resistance, the acceleration due to gravity (g) is constant for all objects regardless of their masses.
  • The time taken to fall from a certain height depends only on the height and the gravitational acceleration, not on the mass of the object.
  • Both bodies, one of mass m and the other of mass 4m, will experience the same gravitational pull and will fall at the same rate.
  • According to the equations of motion, the time taken to reach the ground is given by −−√t=2hg−−√t=2hg−−√t=2hg−−√[Math Processing Error]

t=2hg−−√t=2hg

Code
             \\(t=\sqrt{\frac{2g}{h}} \\), which is the same for both bodies.
  • Therefore, the ratio of the time taken by the two bodies to reach the ground is 1:1.

Additional Information

  • Gravitational Acceleration (g)
  • The acceleration of an object due to the Earth's gravity is approximately 9.8 m/s².
  • It is denoted by the symbol "g" and is a constant value near the Earth's surface.
  • Equations of Motion
  • The equations of motion describe the relationship between the displacement, velocity, acceleration, and time of an object in motion.
  • For free fall, the time taken to reach the ground is calculated using t=2ght=\sqrt{\frac{2g}{h}} −−√t=2hg−−√t=2hg−−√t=2hg−−√[Math Processing Error]

t=2hg−−√t=2hg

  • Mass Independence
  • In the absence of air resistance, the mass of an object does not affect the time it takes to fall to the ground.
  • This principle was famously demonstrated by Galileo's experiments in the late 16th century.
  • Free Fall
  • Free fall is the motion of an object where gravity is the only force acting upon it.
  • In free fall, all objects fall at the same rate regardless of their mass.

Question 12

The HCF of 240, 360 and 480 is: 

  1. AOption (a)

    160

  2. BOption (b)

    120

  3. COption (c)

    360

  4. DOption (d)

    480

View answer & explanation

Correct answer

Answer: (b)B.

120

Why this answer is correct

Shortcut Trick

For HCF, find the difference between the numbers: 360 − 240 = 120 and 480 − 360 = 120.

Since the minimum difference is 120, check if 120 divides all numbers.

240/120 = 2, 360/120 = 3, 480/120 = 4. All are divisible.

∴ The correct answer is 120.

Alternate Method

Given: Numbers are 240, 360, and 480.

Formula Used: Prime Factorization or Common Division Method.

⇒ Prime factors of 240 = 24 × 31 × 51

⇒ Prime factors of 360 = 23 × 32 × 51

⇒ Prime factors of 480 = 25 × 31 × 51

⇒ HCF = Lowest power of common factors = 23 × 31 × 51

⇒ HCF = 8 × 3 × 5 = 120

∴ The correct answer is 120.

Additional Information

HCF (Highest Common Factor)

The greatest number that divides two or more numbers without leaving a remainder. Also known as GCD (Greatest Common Divisor).

Difference Method

HCF of a set of numbers is always a factor of the difference between any two numbers in that set.

LCM and HCF Relationship

For two numbers a and b, the product of the numbers is equal to the product of their HCF and LCM: a × b = HCF × LCM.

Question 13

What is the energy currency for most cellular processes? 

  1. AOption (a)

    NAD 

  2. BOption (b)

    DNA

  3. COption (c)

    ATP

  4. DOption (d)

    RNA

View answer & explanation

Correct answer

Answer: (c)C.

ATP

Why this answer is correct

The correct answer is ATP.

Key Points

  • ATP (Adenosine Triphosphate) is known as the energy currency of the cell as it provides energy for most cellular processes.
  • ATP is produced in the mitochondria through cellular respiration, particularly during the process of oxidative phosphorylation.
  • It releases energy when its phosphate bonds are hydrolyzed, converting ATP to ADP (Adenosine Diphosphate).
  • ATP is crucial for various functions such as muscle contraction, nerve impulse propagation, and chemical synthesis.

Additional Information

  • Cellular Respiration:
  • The process by which cells convert glucose and oxygen into ATP, carbon dioxide, and water.
  • It consists of three main stages: Glycolysis, the Citric Acid Cycle (Krebs Cycle), and Oxidative Phosphorylation.
  • ADP (Adenosine Diphosphate):
  • ADP is the product of ATP dephosphorylation and can be converted back into ATP through cellular respiration.
  • Photosynthesis:
  • In plants, ATP is also produced during the light reactions of photosynthesis, which occurs in the chloroplasts.
  • Enzymes:
  • Various enzymes like ATP synthase play a critical role in the formation of ATP during cellular respiration.

Question 14

The average of the eight numbers is 72. Find the least number if it is 116\frac{1}{16} of the sum of the numbers.

  1. AOption (a)

    36

  2. BOption (b)

    28

  3. COption (c)

    18

  4. DOption (d)

    16

View answer & explanation

Correct answer

Answer: (a)A.

36

Why this answer is correct

Shortcut Trick

Total Sum = Average × Count = 72 × 8

Least Number = 1/16 × Total Sum

Least Number = (1/16) × 72 × 8 = 72 ÷ 2 = 36

∴ The correct answer is 36.

Alternate Method

Given:

Average of 8 numbers = 72

Least number = 1/16 of the Total Sum

Calculations:

⇒ Total Sum = Average × n

⇒ Total Sum = 72 × 8 = 576

⇒ Least Number = (1/16) × 576

⇒ Least Number = 36

∴ The correct answer is 36.

Additional Information

Basic Average Formula

The Average is defined as the Sum of observations divided by the Number of observations. Formula: Average = Σx ÷ n.

Summation Rule

To find the Total Sum when the average is known, multiply the Average by the Total count (n).

Fractional Parts

If a value is a fraction 1/k of the total, the total can be represented as k units and the value as 1 unit.

Question 15

Who among the following has been appointed as the chairperson of the Lokpal in February 2024? 

  1. AOption (a)

    Justice Ajay Manikrao Khanwilkar

  2. BOption (b)

    Justice Manmohan

  3. COption (c)

    Justice Suresh Kumar Kait 

  4. DOption (d)

    Justice Rajiv Shakdher

View answer & explanation

Correct answer

Answer: (a)A.

Justice Ajay Manikrao Khanwilkar

Why this answer is correct

The correct answer is Justice Ajay Manikrao Khanwilkar.

Key Points

  • Justice Ajay Manikrao Khanwilkar has been appointed as the chairperson of the Lokpal in February 2024.
  • He is a retired Judge of the Supreme Court of India, having served from May 2016 to July 2022.
  • Justice Khanwilkar has a rich judicial career, including serving as the Chief Justice of the Madhya Pradesh High Court and as a Judge in the Bombay High Court.
  • His appointment is expected to bring a wealth of experience and integrity to the Lokpal, India's anti-corruption ombudsman institution.

Additional Information

  • Lokpal:
  • The Lokpal and Lokayuktas Act, 2013, establishes a multi-member body to investigate and prosecute corruption cases against public servants in India.
  • The Lokpal is an anti-corruption institution consisting of a chairperson and up to eight members.
  • It has jurisdiction over all Members of Parliament and central government employees in cases of corruption.
  • Previous Chairpersons:
  • Justice Pinaki Chandra Ghose was the first chairperson of the Lokpal, appointed in March 2019.
  • He served until his retirement in May 2022.
  • Selection Process:
  • The chairperson and members of the Lokpal are selected by a committee comprising the Prime Minister, the Chief Justice of India, the Lok Sabha Speaker, the Leader of the Opposition, and an eminent jurist nominated by the President.
  • Role and Powers:
  • The Lokpal has the authority to conduct preliminary inquiries, order investigations, and prosecute cases of corruption.
  • It can also recommend disciplinary action against public servants found guilty of corruption.

Question 16

All activities inside the cell and interactions of the cell with its environment are possible due to three important features observed in almost every cell. Which are the three features?

  1. AOption (a)

    Mitochondria, nucleus and cytoplasm 

  2. BOption (b)

    Plasma membrane, nucleus and Golgi apparatus 

  3. COption (c)

    Plasma membrane, nucleus and cytoplasm 

  4. DOption (d)

    Mitochondria, nucleus and Golgi apparatus 

View answer & explanation

Correct answer

Answer: (c)C.

Plasma membrane, nucleus and cytoplasm 

Why this answer is correct

The correct answer is Plasma membrane, nucleus and cytoplasm.

Key Points

  • The plasma membrane surrounds the cell, providing structural support and regulating the movement of substances in and out of the cell.
  • The nucleus houses the cell's genetic material (DNA) and is responsible for regulating gene expression and cell division.
  • The cytoplasm is a gel-like substance where most cellular activities occur, including metabolic pathways and organelle function.
  • These three features are fundamental to maintaining cell integrity and facilitating cellular processes.

Additional Information

  • Mitochondria: Known as the powerhouse of the cell, mitochondria are responsible for producing ATP through cellular respiration.
  • Golgi apparatus: Involved in modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles.
  • Endoplasmic Reticulum (ER): Exists in two forms, rough ER (with ribosomes) and smooth ER (without ribosomes), and is involved in protein and lipid synthesis.
  • Lysosomes: Contain digestive enzymes to break down waste materials and cellular debris.
  • Cytoskeleton: A network of protein filaments and tubules providing structural support and facilitating cell movement, shape, and division.

Question 17

Given below is a statement followed by two possible reasons numbered I and II. Read the statement carefully and decide which of the two reasons explain(s) the event/observation/information given in the statement.

Statement:

Many trains on the Arakkonam-Chennai route are running several hours late today.

Reasons:

(I) Railways has decided to run two holiday special trains between Kolkata and Patna from November to December 2023.

(II) A major train accident occurred at Arakkonam Junction last night, where seven bogies of an express train derailed and fell across the tracks.

  1. AOption (a)

    Both I and II are possible reasons

  2. BOption (b)

    Only II is a possible reason

  3. COption (c)

    Only I is a possible reason

  4. DOption (d)

    Neither I nor II is a possible reason

View answer & explanation

Correct answer

Answer: (b)B.

Only II is a possible reason

Why this answer is correct

Statement:

Many trains on the Arakkonam-Chennai route are running several hours late today.

Reasons:

  • Reason I: Railways has decided to run two holiday special trains between Kolkata and Patna from November to December 2023.
  • Reason II: A major train accident occurred at Arakkonam Junction last night, where seven bogies of an express train derailed and fell across the tracks.

Analysis:

  • Reason I: This reason is irrelevant to the statement. The fact that holiday trains are running between Kolkata and Patna has no direct impact on trains running on the Arakkonam-Chennai route.
  • Reason II: This reason is highly relevant to the statement. A major train accident at Arakkonam Junction would directly cause delays and disruptions on the Arakkonam-Chennai route.

Conclusion:

Only Reason II (the train accident) is a possible and logical explanation for the delayed trains on the Arakkonam-Chennai route.

Therefore, the correct answer is option 2) Only II is a possible reason.

Question 18

The kinetic energy of a moving body of mass 'm' and velocity 'v' is _______.

  1. AOption (a)

    directly proportional to its velocity but inversely proportional to its mass 

  2. BOption (b)

    directly proportional to its mass but inversely proportional to its velocity 

  3. COption (c)

    inversely proportional to its mass and square of its velocity

  4. DOption (d)

    directly proportional to its mass and square of its velocity

View answer & explanation

Correct answer

Answer: (d)D.

directly proportional to its mass and square of its velocity

Why this answer is correct

The correct answer is option 4.

Key Points

  • Kinetic energy (KE) of a moving body is given by the formula KE = 0.5 * m * v².
  • KE is directly proportional to the mass (m) of the body.
  • KE is directly proportional to the square of the velocity (v²) of the body.
  • Doubling the mass of the body will double its kinetic energy, keeping velocity constant.
  • Doubling the velocity of the body will quadruple its kinetic energy, keeping mass constant.

Additional Information

  • Kinetic Energy (KE): The energy possessed by an object due to its motion, dependent on mass and velocity.
  • Mass (m): The amount of matter in a body, which directly influences the kinetic energy of the body.
  • Velocity (v): The speed of an object in a particular direction, crucial in determining the kinetic energy as it is squared in the formula.
  • Direct Proportionality: When one quantity increases, the other quantity increases at the same rate. KE is directly proportional to both mass and the square of velocity.
  • Energy Conservation: In a closed system, the total energy remains constant. Kinetic energy can be transformed into other forms of energy but the total energy remains the same.

Question 19

If 50 is subtracted from 60% of a number, then the result is 40. 60% of the same number is:

  1. AOption (a)

    120

  2. BOption (b)

    90

  3. COption (c)

    150

  4. DOption (d)

    60

View answer & explanation

Correct answer

Answer: (b)B.

90

Why this answer is correct

Shortcut Trick

According to the question, 60% of a number − 50 = 40.

Directly solving for the required value: 60% of the number = 40 + 50.

⇒ 60% of the number = 90.

∴ The correct answer is 90.

Alternate Method

Let the number be x.

Given: 60% of x − 50 = 40

⇒ (60/100) × x − 50 = 40

⇒ 0.6x − 50 = 40

⇒ 0.6x = 40 + 50

⇒ 0.6x = 90

The question asks for 60% of the same number, which is 0.6x.

⇒ Required Value = 90

∴ The correct answer is 90.

Additional Information

Percentage to Fraction Conversion

To simplify calculations, convert 60% to a fraction: 60/100 = 3/5. The equation becomes (3/5)x − 50 = 40.

Finding the Original Number

If the question asked for the original number: 0.6x = 90 → x = 90 ÷ 0.6 = 150.

Successive Percentage Change

For two successive changes of a% and b%, the net percentage change is [a + b + (ab/100)]%.

Question 20

In a certain code language,

'P + Q' means 'P is the father of Q',

'P - Q' means 'P is the wife of Q',

'P × Q' means 'P is the brother of Q' and

'P ÷ Q' means 'P is the sister of Q'.

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

  1. AOption (a)

    Mother’s father 

  2. BOption (b)

    Mother’s brother 

  3. COption (c)

    Father’s father  

  4. DOption (d)

    Father’s brother 

View answer & explanation

Correct answer

Answer: (a)A.

Mother’s father 

Why this answer is correct

Family tree

In a certain code language,

'P + Q' means 'P is the father of Q',

'P - Q' means 'P is the wife of Q',

'P × Q' means 'P is the brother of Q' and

'P ÷ Q' means 'P is the sister of Q'.

Given,

‘A + B - C + D × E'

So,  A is Mother’s father to E

Hence the correct answer is "Option 1"

Question 21

Refer to the given number and symbol series and answer the question that follows. Counting to be done from left to right only.

(Left) 5 % 4 6 @ 8 $ 7 & 3 Ω 9 2 % # 1 * £ 5 (Right)

How many such symbols are there, each of which is immediately preceded by an odd number and also immediately followed by an odd number?

  1. AOption (a)

    Two

  2. BOption (b)

    More than two

  3. COption (c)

    None 

  4. DOption (d)

    One

View answer & explanation

Correct answer

Answer: (a)A.

Two

Why this answer is correct

Given series: (Left) 5 % 4 6 @ 8 $ 7 & 3 Ω 9 2 % # 1 * £ 5 (Right)

According to the question such symbols which are immediately preceded by an odd number and also immediately followed by an odd number:

Required condition: Odd - Symbol - Odd

((Left) 5 % 4 6 @ 8 $ 7 & 3 Ω 9 2 % # 1 * £ 5 (Right)

Thus, there are two such symbols which are immediately preceded by an odd number and also immediately followed by an odd number.

Hence, "Option 1" is the correct answer.

Question 22

Which of the following statements about the reaction of a non-metallic oxide with a base is/are correct?

Statement I: The reaction of non-metallic oxide with base produces salt and water.

Statement II: Non-metallic oxides are acidic in nature.

  1. AOption (a)

    Neither statement I nor II is correct. 

  2. BOption (b)

    Only statement I is correct.  

  3. COption (c)

    Both statements I and II are correct. 

  4. DOption (d)

    Only statement II is correct. 

View answer & explanation

Correct answer

Answer: (c)C.

Both statements I and II are correct. 

Why this answer is correct

The correct answer is 3) Both statements I and II are correct.

Key Points

  • Non-metallic oxides such as CO₂ and SO₂ react with bases to form salt and water, demonstrating their acidic nature.
  • Statement I is correct as it describes the neutralization reaction between a non-metallic oxide and a base.
  • Statement II is correct as non-metallic oxides are indeed acidic in nature, meaning they react with bases.
  • Examples include CO₂ reacting with NaOH to form Na₂CO₃ (sodium carbonate) and water.

Additional Information

  • Acid-Base Reactions:
  • Acid-base reactions involve the transfer of protons (H⁺) from the acid to the base.
  • These reactions result in the formation of water and a salt.
  • Examples of Non-Metallic Oxides:
  • Carbon dioxide (CO₂), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂) are common non-metallic oxides.
  • These oxides typically react with water to form acids.
  • Neutralization Reactions:
  • In a neutralization reaction, an acid and a base react to form water and a salt.
  • This type of reaction is essential in various industrial and biological processes.
  • Properties of Acids and Bases:
  • Acids have a sour taste and can turn blue litmus paper red.
  • Bases have a bitter taste and can turn red litmus paper blue.

Question 23

Gastric glands present in the wall of the stomach do NOT release: 

  1. AOption (a)

    pepsin  

  2. BOption (b)

    saliva 

  3. COption (c)

    hydrochloric acid 

  4. DOption (d)

    mucus

View answer & explanation

Correct answer

Answer: (b)B.

saliva 

Why this answer is correct

The correct answer is saliva.

Key Points

  • The gastric glands in the stomach are responsible for secreting various substances that aid in digestion.
  • These glands release pepsinogen, which is converted to pepsin in the presence of hydrochloric acid.
  • Hydrochloric acid (HCl) is secreted by the parietal cells in the gastric glands and helps in maintaining an acidic environment.
  • Mucus is also secreted by the gastric glands to protect the stomach lining from the corrosive effects of HCl and digestive enzymes.
  • Saliva is not secreted by the gastric glands; it is produced by the salivary glands located in the mouth.

Additional Information

  • Pepsinogen: An inactive enzyme precursor secreted by the chief cells in the stomach, which is activated to pepsin by the acidic environment.
  • Hydrochloric Acid (HCl): Produced by the parietal cells in the stomach, it creates an acidic environment, which is essential for the activation of pepsin and for killing pathogens.
  • Mucus: Secreted by the mucous cells in the stomach lining, it forms a protective barrier to prevent the stomach lining from being digested by gastric juices.
  • Saliva: A digestive fluid produced by the salivary glands in the mouth, containing enzymes like amylase that begin the process of digestion.
  • Gastric Glands: Located in the lining of the stomach, these glands include mucous cells, parietal cells, and chief cells, each secreting different substances necessary for digestion.

Question 24

A single discount equivalent to successive discounts of 40% and 20% is: 

  1. AOption (a)

    55% 

  2. BOption (b)

    50% 

  3. COption (c)

    60% 

  4. DOption (d)

    52%

View answer & explanation

Correct answer

Answer: (d)D.

52%

Why this answer is correct

Shortcut Trick

Net Successive Discount = a + b − (a × b) ÷ 100

Here, a = 40 and b = 20.

Effective Discount = 40 + 20 − (40 × 20) ÷ 100

Effective Discount = 60 − 800 ÷ 100 = 60 − 8 = 52%.

∴ The correct answer is 52%.

Alternate Method

Given: First discount = 40%, Second discount = 20%. Formulas: SP = MP × (100 − d1)% × (100 − d2)% | Equivalent Discount = (MP − SP) ÷ MP × 100

⇒ Let the Marked Price (MP) be 100.

⇒ Price after 40% discount = 100 − 40 = 60.

⇒ Price after 20% additional discount = 60 − (20% of 60) = 60 − 12 = 48.

⇒ Total Discount = MP − Final SP = 100 − 48 = 52.

⇒ Equivalent Discount Percentage = (52 ÷ 100) × 100 = 52%.

∴ The correct answer is 52%.

Additional Information

Successive Discounts

When two or more discounts are applied one after another on the reduced price, they are called successive discounts. The net discount is always less than the sum of individual discount rates.

Marked Price & Discount

Discount is always calculated on the Marked Price (MP). Selling Price (SP) = Marked Price − Discount.

Question 25

How much prize money was announced by the BCCI for the men’s T20 cricket World Cup 2024 winner team?

  1. AOption (a)

    ₹150 crore

  2. BOption (b)

    ₹125 crore 

  3. COption (c)

    ₹50 crore

  4. DOption (d)

    ₹100 crore

View answer & explanation

Correct answer

Answer: (b)B.

₹125 crore 

Why this answer is correct

The correct answer is Option 2: ₹125 crore.

Key Points

  • The Board of Control for Cricket in India (BCCI) announced ₹125 crore as the prize money for the winner of the men's T20 World Cup 2024.
  • This announcement aligns with BCCI's commitment to promoting cricket and providing substantial rewards for outstanding performances.
  • The prize money reflects the increasing commercial success and popularity of T20 cricket globally.
  • BCCI's decision aims to incentivize teams and players, enhancing the competitive spirit of the tournament.
  • This amount is significantly higher than previous prize distributions, demonstrating the growing financial stakes in international cricket.

Additional Information

  • Men's T20 World Cup:
  • The ICC Men's T20 World Cup is an international cricket championship organized by the International Cricket Council (ICC).
  • The tournament features teams from around the world competing in the T20 format, which is a shorter, more dynamic version of cricket.
  • The first T20 World Cup was held in 2007, and it has since become one of the most popular events in the sport.
  • BCCI (Board of Control for Cricket in India):
  • BCCI is the governing body for cricket in India, overseeing all domestic and international cricket operations in the country.
  • Founded in 1928, BCCI is one of the richest and most powerful cricket boards in the world.
  • It is responsible for organizing major cricket tournaments in India, including the Indian Premier League (IPL).
  • Commercial Success of T20 Cricket:
  • T20 cricket has revolutionized the sport, attracting a wider audience with its fast-paced and entertaining format.
  • It has led to significant commercial opportunities, including broadcasting rights, sponsorships, and merchandise sales.
  • The format has also seen the emergence of various T20 leagues around the world, such as the IPL, Big Bash League (BBL), and Caribbean Premier League (CPL).
  • Prize Money in Cricket:
  • Prize money in cricket tournaments serves as a major incentive for teams and players, promoting higher levels of performance and competition.
  • It also reflects the economic growth and financial health of the sport, driven by increasing viewership and commercial interests.
  • Significant prize money allocations are seen in major tournaments like the ICC Cricket World Cup, IPL, and T20 World Cup.

Question 26

Rs. 2,000 is divided between A and B such that half of A's part and one-third of B's part are equal. What is B's part (in Rs.)?  

  1. AOption (a)

    1,200

  2. BOption (b)

    600

  3. COption (c)

    800

  4. DOption (d)

    1,000

View answer & explanation

Correct answer

Answer: (a)A.

1,200

Why this answer is correct

Shortcut Trick

Ratio of A : B is found by the inverse of their fractional coefficients.

(1/2) × A = (1/3) × B ⇒ A : B = 2 : 3.

Total ratio parts = 2 + 3 = 5 units. Given 5 units = ₹2,000.

1 unit = 400. B's part (3 units) = 3 × 400 = ₹1,200.

∴ The correct answer is ₹1200.

Alternate Method

Given: Total sum = ₹2,000. Condition: (1/2) of A = (1/3) of B.

⇒ Let (1/2)A = (1/3)B = k

⇒ A = 2k and B = 3k

⇒ A + B = 2k + 3k = 5k

⇒ 5k = 2,000

⇒ k = 2,000 ÷ 5 = 400

⇒ B's part = 3k = 3 × 400 = 1,200

∴ The correct answer is ₹1200.

Additional Information

Ratio of Equality

If aA = bB, then the ratio A : B is b : a. This is often used in division problems involving fractions of shares.

Compound Ratio

The ratio of the products of the corresponding terms of two or more ratios is called the compound ratio (e.g., (a×c) : (b×d)).

Proportional Division

To divide a quantity S in ratio x : y, the parts are [x/(x+y)] × S and [y/(x+y)] × S.

Question 27

Which of the following is NOT a role played by NITI Aayog in the localisation of SDGs in India?

  1. AOption (a)

    Preparing the National Indicator Framework (NIF)

  2. BOption (b)

    Fostering competitive federalism among states and UTs

  3. COption (c)

    Benchmarking states based on SDG performance metrics

  4. DOption (d)

    Serving as a platform for collaboration among states

View answer & explanation

Correct answer

Answer: (a)A.

Preparing the National Indicator Framework (NIF)

Why this answer is correct

The correct answer is 1.

Key Points

  • NITI Aayog does not prepare the National Indicator Framework (NIF); this task is primarily undertaken by the Ministry of Statistics and Programme Implementation (MoSPI).
  • The NIF is crucial for monitoring the progress of Sustainable Development Goals (SDGs) and is developed in consultation with various stakeholders, including government bodies, international agencies, and civil society organizations.
  • NITI Aayog plays a significant role in fostering competitive federalism by encouraging states and Union Territories (UTs) to actively participate in achieving SDG targets.
  • Benchmarking states based on SDG performance metrics is another crucial function of NITI Aayog, helping to identify areas that need improvement and promoting best practices.
  • NITI Aayog serves as a collaborative platform for states and UTs, facilitating the exchange of ideas and strategies to achieve the SDGs effectively.

Additional Information

  • Sustainable Development Goals (SDGs):
  • The SDGs are a set of 17 global goals adopted by all United Nations Member States in 2015 as part of the 2030 Agenda for Sustainable Development.
  • The goals cover a broad range of social, economic, and environmental development issues.
  • They aim to end poverty, protect the planet, and ensure prosperity for all.
  • NITI Aayog:
  • The National Institution for Transforming India, known as NITI Aayog, is a policy think-tank of the Government of India, established with the aim to achieve sustainable development goals.
  • It was formed on January 1, 2015, replacing the Planning Commission.
  • NITI Aayog promotes cooperative federalism through structured support initiatives and mechanisms with the states.
  • National Indicator Framework (NIF):
  • The NIF is designed to track the progress of SDG targets in India.
  • It includes a comprehensive set of indicators that are periodically reviewed and updated.
  • The framework helps in identifying data gaps and areas that require policy intervention.
  • Ministry of Statistics and Programme Implementation (MoSPI):
  • MoSPI is responsible for the development and maintenance of statistical standards and the coordination of statistical activities in India.
  • It is the nodal agency for the preparation of the National Indicator Framework.
  • MoSPI ensures the availability of reliable, timely, and credible data for policymakers and stakeholders.

Question 28

If the focal length of a lens is -25 cm, the power of the lens will be: 

  1. AOption (a)

    +0.04D 

  2. BOption (b)

    +4D 

  3. COption (c)

    -4D 

  4. DOption (d)

    -0.04D 

View answer & explanation

Correct answer

Answer: (c)C.

-4D 

Why this answer is correct

The correct answer is -4D.

Key Points

  • The power of a lens (P) is calculated using the formula P = 1/f, where f is the focal length in meters.
  • Given the focal length (f) is -25 cm, which is -0.25 meters (since 1 cm = 0.01 meters).
  • Substituting the value into the formula: P = 1 / -0.25 = -4 Diopters (D).
  • A negative power indicates that the lens is a diverging (concave) lens.
  • Therefore, the power of the lens is -4D, making option 3 the correct answer.

Additional Information

  • Diopter (D): A unit of measurement for the optical power of a lens, defined as the reciprocal of the focal length in meters.
  • Focal Length (f): The distance between the center of a lens and its focus, where parallel rays of light converge or appear to diverge.
  • Concave Lens: A lens that diverges light rays passing through it, typically used to correct myopia (nearsightedness).
  • Convex Lens: A lens that converges light rays passing through it, typically used to correct hyperopia (farsightedness).
  • Lens Formula: The relationship between the object distance (u), image distance (v), and focal length (f) of a lens, given by 1/f = 1/v - 1/u.

Question 29

Match the class of organic compounds (Column I) with the suffix used (Column II). 

Column IColumn II
i.Ketonea.-al (-CHO)
ii.Alkeneb.-one (C=O)
iii.Aldehydec.-ene (-C=C-)
iv.Carboxylic acidd.-oic acid (-COOH)
  1. AOption (a)

    i - c, ii - d, iii - b, iv - a

  2. BOption (b)

    i - b, ii - c, iii - a, iv - d

  3. COption (c)

    i - c, ii - b, iii - a, iv - d

  4. DOption (d)

    i - b, ii - c, iii - d, iv - a

View answer & explanation

Correct answer

Answer: (b)B.

i - b, ii - c, iii - a, iv - d

Why this answer is correct

The correct answer is 2) i - b, ii - c, iii - a, iv - d.

Key Points

  • Ketone uses the suffix -one indicating the presence of a carbonyl group (C=O).
  • Alkene uses the suffix -ene indicating the presence of a carbon-carbon double bond (-C=C-).
  • Aldehyde uses the suffix -al indicating the presence of a formyl group (-CHO).
  • Carboxylic acid uses the suffix -oic acid indicating the presence of a carboxyl group (-COOH).

Additional Information

  • Keto Group (C=O):
  • Found in ketones, characterized by the carbonyl group bonded to two carbon atoms.
  • Example: Propanone (acetone), the simplest ketone.
  • Alkene Group (-C=C-):
  • Alkenes are hydrocarbons with at least one carbon-carbon double bond.
  • Example: Ethene (ethylene), used in the production of polyethylene.
  • Formyl Group (-CHO):
  • Found in aldehydes, characterized by a carbonyl group bonded to at least one hydrogen atom.
  • Example: Methanal (formaldehyde), used in the production of resins.
  • Carboxyl Group (-COOH):
  • Found in carboxylic acids, characterized by a carbonyl and hydroxyl group attached to the same carbon.
  • Example: Ethanoic acid (acetic acid), a key component of vinegar.

Question 30

A father’s age is seven times that of his son’s age. Three years from now, the age of the father will be five times that of his son’s age. After how many years will their combined age be 58 years? 

  1. AOption (a)

    2 years

  2. BOption (b)

    4 years 

  3. COption (c)

    6 years

  4. DOption (d)

    5 years

View answer & explanation

Correct answer

Answer: (d)D.

5 years

Why this answer is correct

Shortcut Trick

Ratio of Father : Son currently is 7 : 1 (diff = 6).

Ratio after 3 years is 5 : 1 (diff = 4). To equate difference, multiply 1st by 2 and 2nd by 3.

New ratios: 14 : 2 → 15 : 3. Change of 1 unit = 3 years. Current ages: 42 and 6.

Current total age = 48 years. Target total = 58 years. Required increase = 10 years.

Since two people are involved, years needed = 10 ÷ 2 = 5 years.

∴ The correct answer is 5 years.

Alternate Method

Given: Present age ratio 7:1. After 3 years, ratio becomes 5:1.

Let Son's present age = x and Father's present age = 7x.

⇒ (7x + 3) = 5 × (x + 3)

⇒ 7x + 3 = 5x + 15

⇒ 2x = 12 ⇒ x = 6

⇒ Father's present age = 42 years, Son's present age = 6 years.

⇒ Let after 'n' years, sum be 58: (42 + n) + (6 + n) = 58

⇒ 48 + 2n = 58 ⇒ 2n = 10 ⇒ n = 5

∴ The correct answer is 5 years.

Additional Information

Age Difference Property

The difference between the ages of two people remains constant throughout their lives, regardless of the number of years passed.

Sum of Ages Property

If 'n' years pass, the sum of the ages of 'k' people increases by n × k years.

Ratio of Ages

Ratios of ages change over time; they can only be used directly if the time frame (present, past, future) is the same for all terms.

Question 31

The value of sin⁡248∘+sin⁡242∘tan⁡240∘−cosec250∘\frac{\sin^2 48^\circ+\sin ^2 42^\circ}{\tan^2 40^\circ-\rm cosec^2 50^\circ} is:

  1. AOption (a)

    0

  2. BOption (b)

    -1

  3. COption (c)

    2

  4. DOption (d)

    1

View answer & explanation

Correct answer

Answer: (b)B.

-1

Why this answer is correct

Shortcut Trick

Identify complementary angles: 48° + 42° = 90° and 40° + 50° = 90°.

Apply shortcut results for complementary pairs:

Numerator: sin2 A + sin2 (90−A) = 1.

Denominator: tan2 B − cosec2 (90−B) = tan2 B − sec2 B = −1.

Result = 1 ÷ (−1) = −1.

∴ The correct answer is -1.

Alternate Method

Given: Expression = (sin2 48° + sin2 42°) ÷ (tan2 40° − cosec2 50°)

Formula Used:

  1. Complementary Angles: sin θ = cos(90° − θ) and cosec θ = sec(90° − θ)
  2. Trigonometric Identities: sin2 θ + cos2 θ = 1 and sec2 θ − tan2 θ = 1

⇒ Numerator = sin2 48° + sin2 (90° − 48°)

⇒ Numerator = sin2 48° + cos2 48° = 1

⇒ Denominator = tan2 40° − cosec2 (90° − 40°)

⇒ Denominator = tan2 40° − sec2 40°

⇒ Since sec2 θ − tan2 θ = 1, then tan2 θ − sec2 θ = −1

⇒ Expression = 1 ÷ (−1) = −1

∴ The correct answer is -1.

Additional Information

Complementary Angle Relationships

For any angle θ, sin θ = cos(90° − θ), tan θ = cot(90° − θ), and sec θ = cosec(90° − θ).

Fundamental Trigonometric Identities

  1. sin2 θ + cos2 θ = 1 | 2. 1 + tan2 θ = sec2 θ | 3. 1 + cot2 θ = cosec2 θ.

Sign Convention for Identities

Always check the order of terms; for example, sec2 θ − tan2 θ = 1, but tan2 θ − sec2 θ = −1.

Question 32

In an ecosystem, physical factors like temperature, rainfall, wind, soil and minerals are: 

  1. AOption (a)

    decomposers  

  2. BOption (b)

    abiotic components 

  3. COption (c)

    living components 

  4. DOption (d)

    biotic components 

View answer & explanation

Correct answer

Answer: (b)B.

abiotic components 

Why this answer is correct

The correct answer is abiotic components.

Key Points

  • Abiotic components refer to the non-living physical and chemical elements in an ecosystem.
  • These components include factors such as temperature, rainfall, wind, soil, and minerals.
  • Abiotic factors significantly influence the types of organisms that can live in an ecosystem and their distribution.
  • Examples of abiotic components also include sunlight, water, air, and nutrients.
  • Abiotic components interact with biotic components (living organisms) to create a balanced ecosystem.

Additional Information

  • Biotic Components:
  • Biotic components are the living organisms in an ecosystem, such as plants, animals, fungi, and microorganisms.
  • They interact with abiotic components to sustain life and maintain ecological balance.
  • Decomposers:
  • Decomposers are organisms like bacteria and fungi that break down dead organic matter, returning nutrients to the soil.
  • They play a crucial role in nutrient cycling within ecosystems.
  • Importance of Abiotic Factors:
  • Abiotic factors determine the physical environment in which biotic components live.
  • They influence growth rates, reproductive success, and survival of organisms.
  • Interaction of Abiotic and Biotic Factors:
  • Both sets of components interact to create a dynamic and functional ecosystem.
  • Changes in abiotic factors can lead to shifts in the types of biotic communities present.

Question 33

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

DJC, YEX, TZS, OUN,?

  1. AOption (a)

    JRI

  2. BOption (b)

    JPM

  3. COption (c)

    JRM

  4. DOption (d)

    JPI

View answer & explanation

Correct answer

Answer: (d)D.

JPI

Why this answer is correct

Logic followed here is,

Hence the correct answer is "Option 4"

Question 34

Select the correct statement related to the characteristics of prokaryotic cell. 

  1. AOption (a)

    It has more than one chromosome. 

  2. BOption (b)

    It has a single chromosome. 

  3. COption (c)

    Nuclear region is well defined and surrounded by nuclear membrane.  

  4. DOption (d)

    Membrane bound cell organelles are present. 

View answer & explanation

Correct answer

Answer: (b)B.

It has a single chromosome. 

Why this answer is correct

The correct answer is It has a single chromosome..

Key Points

  • Prokaryotic cells typically contain a single, circular chromosome, which is not enclosed in a nucleus.
  • These cells lack a membrane-bound nucleus; instead, their genetic material is located in a nucleoid region.
  • Prokaryotic cells do not possess membrane-bound organelles such as mitochondria or chloroplasts.
  • Examples of prokaryotic cells include bacteria and archaea.

Additional Information

  • Plasmids: Small, circular DNA molecules found in prokaryotes that are separate from the chromosomal DNA and can replicate independently.
  • Ribosomes: Prokaryotic ribosomes are 70S, composed of 50S and 30S subunits, and are involved in protein synthesis.
  • Cell Wall: Most prokaryotes have a rigid cell wall made of peptidoglycan (in bacteria) or pseudopeptidoglycan (in archaea) that provides structural support and protection.
  • Binary Fission: Prokaryotic cells reproduce asexually through a process called binary fission, where the cell divides into two genetically identical daughter cells.

Question 35

Besides products of photosynthesis, which of the following substances are transported by the phloem in plants? 

  1. AOption (a)

    Only Sucrose 

  2. BOption (b)

    Only Water 

  3. COption (c)

    Only Amino acids 

  4. DOption (d)

    Both amino acids and sucrose 

View answer & explanation

Correct answer

Answer: (d)D.

Both amino acids and sucrose 

Why this answer is correct

The correct answer is Both amino acids and sucrose.

Key Points

  • Phloem transports multiple organic compounds, including both amino acids and sucrose, essential for plant growth and development.
  • Sucrose is the primary form of carbohydrate transported through the phloem, providing energy to various parts of the plant.
  • Amino acids are also transported through the phloem to support protein synthesis in growing regions.
  • The transport of these substances ensures that non-photosynthetic parts of the plant, like roots and developing fruits, receive necessary nutrients.

Additional Information

  • Phloem Structure:
  • The phloem consists of sieve tube elements, companion cells, phloem fibers, and phloem parenchyma, which work together to transport nutrients.
  • Translocation Process:
  • The movement of nutrients through the phloem is known as translocation and is driven by pressure flow mechanisms.
  • Source to Sink Movement:
  • Nutrients are transported from 'source' regions (photosynthetic tissues) to 'sink' regions (growing or storage tissues).
  • Role in Plant Health:
  • Efficient phloem transport is crucial for overall plant health, affecting growth, reproduction, and response to environmental stresses.

Question 36

If 'A’ stands for ‘÷’, ‘B’ stands for '×’, 'C’ stands for ‘+’, and ‘D’ stands for ‘-’,

then the resultant of which of the following would be 99?

  1. AOption (a)

    28 D 39 A 3 C 12 B 7 

  2. BOption (b)

    28 C 39 B 3 D 12 A 7

  3. COption (c)

    28 A 39 D 3 B 12 C 7

  4. DOption (d)

    28 B 39 C 3 A 12 D 7

View answer & explanation

Correct answer

Answer: (a)A.

28 D 39 A 3 C 12 B 7 

Why this answer is correct

BODMAS Rule:

Decoding the given information:

AlphabetABCD
Meaning÷×+−

Now replacing the signs from left to right using BODMAS Rule in each option, we get:

Option 1) 28 D 39 A 3 C 12 B 7

⇒ 28 - 39 ÷ 3 + 12 × 7

⇒ 28 - 13 + 84

⇒ 15 + 84 = 99 (Matches)

Option 2) 28 C 39 B 3 D 12 A 7

⇒ 28 + 39 × 3 - 12 ÷ 7

⇒ 28 + 117 - 1.71 (approx.)

⇒ 145 - 1.71 = 143.29 (approx.) (Does not match 99)

Option 3) 28 A 39 D 3 B 12 C 7

⇒ 28 ÷ 39 - 3 × 12 + 7

⇒ 0.72 (approx.) - 36 + 7

⇒ -28.28 (approx.) (Does not match 99)

Option 4) 28 B 39 C 3 A 12 D 7

⇒ 28 × 39 + 3 ÷ 12 - 7

⇒ 1092 + 0.25 - 7

⇒ 1085.25 (Does not match 99)

Therefore, the correct answer is option 1) 28 D 39 A 3 C 12 B 7

Question 37

A dentist usually uses: 

  1. AOption (a)

    a plane mirror 

  2. BOption (b)

    a convex mirror 

  3. COption (c)

    a plano-convex mirror  

  4. DOption (d)

    a concave mirror 

View answer & explanation

Correct answer

Answer: (d)D.

a concave mirror 

Why this answer is correct

The correct answer is a concave mirror.

Key Points

  • A dentist uses a concave mirror to examine the teeth.
  • Concave mirrors provide a magnified and upright image of the teeth, which helps in detailed examination.
  • The curved surface of a concave mirror helps in focusing light, providing better illumination in the oral cavity.
  • Concave mirrors are preferred because they allow dentists to see a larger area of the mouth clearly.

Additional Information

  • Convex Mirror:
  • A convex mirror diverges light rays and is used for a wider field of view, such as in vehicle side mirrors.
  • It provides a smaller, upright, and diminished image, which is not suitable for dental examination.
  • Plane Mirror:
  • A plane mirror reflects light without altering the size of the image.
  • It provides a virtual, upright image of the same size as the object, but it does not magnify, making it less useful for detailed dental work.
  • Plano-Convex Mirror:
  • A plano-convex mirror is typically used in focusing applications, such as in telescopes and laser systems.
  • It is not used in dental practices due to its specific focusing properties.
  • Optical Properties:
  • Concave mirrors converge light rays to a focal point, allowing for magnification of the image.
  • Convex mirrors and plane mirrors do not offer the same level of magnification and focus required for dental examinations.

Question 38

A porter lifts a luggage weighing 10 kg from the ground and puts it on his head 1 m above the ground. Then the work done by him on the luggage (g is acceleration due to gravity in SI unit) is ________

  1. AOption (a)

    10g J

  2. BOption (b)

    18g J

  3. COption (c)

    20g J

  4. DOption (d)

    15g J

View answer & explanation

Correct answer

Answer: (a)A.

10g J

Why this answer is correct

The correct answer is 10g J.

Key Points

  • The work done (W) by the porter on the luggage is calculated using the formula W = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height.
  • Here, m = 10 kg, g = 9.8 m/s² (standard value of acceleration due to gravity), and h = 1 m.
  • Substituting the values, W = 10 kg × 9.8 m/s² × 1 m.
  • Thus, the work done by the porter is 10g joules (since g is the symbol for 9.8 m/s²).

Additional Information

  • Work Done:
  • In physics, work is defined as a measure of energy transfer that occurs when an object is moved over a distance by an external force.
  • The formula for work done is W = F × d × cos(θ), where F is the force applied, d is the displacement, and θ is the angle between the force and displacement vectors.
  • SI Unit of Work:
  • The SI unit of work is the joule (J).
  • 1 joule is equivalent to 1 newton-meter (N·m).
  • Gravitational Force:
  • Gravitational force is the force of attraction between two masses.
  • It is given by the formula F = mg, where m is the mass and g is the acceleration due to gravity.
  • Energy Transfer:
  • Work is a form of energy transfer from one system to another.
  • When work is done on an object, energy is transferred to the object, often resulting in a change in its kinetic or potential energy.

Question 39

The Union Finance Minister, on 9 November 2024, inaugurated Nari Shakti Branches of which of the following banks in Bengaluru, Chennai, Visakhapatnam, and Jaipur? 

  1. AOption (a)

    Bank of Baroda 

  2. BOption (b)

    State Bank of India 

  3. COption (c)

    Canara Bank 

  4. DOption (d)

    Union Bank of India 

View answer & explanation

Correct answer

Answer: (d)D.

Union Bank of India 

Why this answer is correct

The correct answer is Union Bank of India.

Key Points

  • Union Finance Minister inaugurated Nari Shakti Branches of Union Bank of India on 9 November 2024.
  • The branches are located in Bengaluru, Chennai, Visakhapatnam, and Jaipur.
  • Nari Shakti Branches aim to empower women by providing specialized banking services.
  • The initiative is part of the bank's efforts to promote financial inclusion among women.

Additional Information

  • Financial Inclusion:
  • Financial inclusion refers to making financial services accessible and affordable to all individuals, especially those underserved by the banking sector.
  • It aims to ensure that everyone has access to basic financial services like savings, credit, insurance, and pensions.
  • Financial inclusion is crucial for reducing poverty and fostering economic growth.
  • Women Empowerment:
  • Women empowerment involves creating an environment where women can make independent decisions for their personal development.
  • It includes providing access to education, employment, and financial services.
  • Empowered women contribute significantly to the economic and social development of their communities.
  • Union Bank of India:
  • Union Bank of India is one of the largest government-owned banks in India.
  • It was established in 1919 and has its headquarters in Mumbai.
  • The bank provides a wide range of banking and financial services to its customers.

Question 40

Sodium or potassium salt of long chain carboxylic acid is known as which of the following?

  1. AOption (a)

    Micelle 

  2. BOption (b)

    Both detergent and soap  

  3. COption (c)

    Detergent 

  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

  • Sodium or potassium salts of long chain carboxylic acids are commonly referred to as soaps.
  • Soaps are produced through a chemical process called saponification, where fats and oils react with a base.
  • In the saponification process, triglycerides (fats/oils) are hydrolyzed to produce glycerol and soap.
  • Soaps are effective in cleaning because they are surfactants, which means they lower the surface tension of water, allowing it to mix with oils and dirt.

Additional Information

  • Micelle:
  • A micelle is an aggregate of surfactant molecules dispersed in a liquid colloid forming a molecular assembly.
  • Micelles are formed when the concentration of surfactant molecules exceeds the critical micelle concentration (CMC).
  • They play a key role in the cleansing action of soaps and detergents by trapping grease and dirt.
  • Detergents:
  • Detergents are synthetic cleaning agents, typically made from petrochemicals.
  • Unlike soaps, detergents can perform well in hard water as they do not form scum.
  • Detergents are also surfactants and work by emulsifying oils and dirt.
  • Saponification:
  • Saponification is a chemical reaction that produces soap from fats/oils and an alkali.
  • The reaction results in the formation of glycerol and soap.
  • This process is crucial in traditional soap making and industrial soap production.
  • Surfactants:
  • Surfactants are compounds that lower the surface tension between two liquids or a liquid and a solid.
  • They are the active agents in soaps and detergents that enable them to clean effectively.
  • Surfactants can be classified as anionic, cationic, nonionic, or amphoteric based on their charge.

Question 41

In how many years will a sum of Rs. 12,000 become Rs. 14,520 at a rate of 10% per annum on compound interest, compounded annually? 

  1. AOption (a)

    2

  2. BOption (b)

    5

  3. COption (c)

    3

  4. DOption (d)

    4

View answer & explanation

Correct answer

Answer: (a)A.

2

Why this answer is correct

Shortcut Trick

Using the ratio method: Principal (P) : Amount (A) = 12000 : 14520

Simplifying the ratio: P : A = 120 : 145.2 = 100 : 121

Since 100 : 121 = (10)2 : (11)2, which corresponds to (1 + 10%)2, the time period is 2 years.

∴ The correct answer is 2 years.

Alternate Method

Given: Principal (P) = ₹12,000, Amount (A) = ₹14,520, Rate (R) = 10% per annum.

Formula Used: A = P × (1 + R/100)t, where t is the time in years.

Calculations:

→ 14520 = 12000 × (1 + 10/100)t

→ 14520 ÷ 12000 = (11/10)t

→ 1452 ÷ 1200 = (1.1)t

→ 121 ÷ 100 = (1.1)t

→ 1.21 = (1.1)t

→ (1.1)2 = (1.1)t

⇒ t = 2 years

∴ The correct answer is 2 years.

Additional Information

Compound Interest Formula

The amount accumulated on principal P at rate R% compound interest per annum compounded annually for t years is given by A = P(1 + R/100)t.

Effective Rate of Interest

For a rate of 10% compounded annually, the effective rate for 2 years is calculated using successive percentage change: 10 + 10 + (10 × 10)/100 = 21%.

Question 42

If the power of a lens is +1 Dioptre, then the focal length of the lens will be:  

  1. AOption (a)

    0.75 m

  2. BOption (b)

    0.5 m

  3. COption (c)

    0.25 m

  4. DOption (d)

    1 m

View answer & explanation

Correct answer

Answer: (d)D.

1 m

Why this answer is correct

The correct answer is +1 Dioptre.

Key Points

  • The power of a lens (P) in dioptres is the reciprocal of the focal length (f) in meters, represented as P = 1/f.
  • If the power of the lens is +1 Dioptre, the focal length (f) can be calculated using the formula: f = 1/P.
  • Substituting the given power, f = 1/1 = 1 meter.
  • A positive dioptre value indicates that the lens is a converging lens, typically used for correcting hyperopia (farsightedness).

Additional Information

  • Dioptre (D): A unit of measurement for the optical power of a lens, defined as the reciprocal of the focal length in meters (1/m).
  • Focal Length (f): The distance between the lens and the point where parallel rays of light converge (for a converging lens) or appear to diverge (for a diverging lens).
  • Converging Lens: Also known as a convex lens, it bends light rays inward, bringing them to a focus. Used in applications like magnifying glasses and corrective lenses for hyperopia.
  • Diverging Lens: Also known as a concave lens, it spreads out light rays that have been refracted through it. Used in applications like corrective lenses for myopia (nearsightedness).
  • Hyperopia (Farsightedness): A condition where distant objects are seen more clearly than near ones. Converging lenses with positive dioptre values are used for correction.

Question 43

TQSO is related to MJLH in a certain way based on the English alphabetical order. In the same way, VSUQ is related to OLNJ. To which of the following options is ROQM related, following the same logic ?

  1. AOption (a)

    KHFJ

  2. BOption (b)

    KHJF

  3. COption (c)

    HKFJ

  4. DOption (d)

    HKJF

View answer & explanation

Correct answer

Answer: (b)B.

KHJF

Why this answer is correct

Logic followed here is,

Logic: Every letter is decreased by 7.

Given,

TQSO is related to MJLH

For, VSUQ is related to OLNJ

Similarly for ROQM is related to KHJF.

Hence the correct answer is "Option 2"

Question 44

When a more reactive metal is placed in a salt solution containing a less reactive metal, it replaces the less reactive metal. This reaction is known as ______.

  1. AOption (a)

    Displacement reaction

  2. BOption (b)

    Combination reaction

  3. COption (c)

    Neutralisation reaction

  4. DOption (d)

    Decomposition reaction

View answer & explanation

Correct answer

Answer: (a)A.

Displacement reaction

Why this answer is correct

The correct answer is Displacement reaction.

Key Points

  • A displacement reaction occurs when a more reactive metal displaces a less reactive metal from its compound.
  • This type of reaction is typically observed in aqueous solutions where metals are involved.
  • For example, when zinc is placed in a copper sulfate solution, zinc displaces copper, forming zinc sulfate and copper metal.
  • Displacement reactions are a subset of redox reactions, where the more reactive metal is oxidized and the less reactive metal is reduced.
  • These reactions are used in various industrial processes, including metal extraction and purification.

Additional Information

  • Reactivity Series:
  • The reactivity series is a list of metals arranged in order of decreasing reactivity.
  • It helps predict the outcomes of displacement reactions.
  • Highly reactive metals like potassium and sodium are at the top, while less reactive metals like gold and platinum are at the bottom.
  • Redox Reactions:
  • Redox reactions involve the transfer of electrons between two substances.
  • Oxidation refers to the loss of electrons, while reduction refers to the gain of electrons.
  • Displacement reactions are a specific type of redox reaction.
  • Applications:
  • Displacement reactions are used in metallurgy for extracting metals from their ores.
  • They are also utilized in galvanic cells to generate electrical energy.
  • These reactions are fundamental in the manufacturing of various chemicals.
  • Examples:
  • Iron displacing copper from copper sulfate solution: Fe + CuSO4 → FeSO4 + Cu
  • Magnesium displacing zinc from zinc sulfate solution: Mg + ZnSO4 → MgSO4 + Zn

Question 45

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)

    JNK

  2. BOption (b)

    OSP

  3. COption (c)

    TXV

  4. DOption (d)

    EIF

View answer & explanation

Correct answer

Answer: (c)C.

TXV

Why this answer is correct

Logic follow here is that the first letter is decreased by 4 and second letter is decreased by 3.

Option 1) JNK

Option 2) OSP

Option 3) TXV

Does not follow the same logic.

Option 4) EIF

Hence the correct answer is "Option 3"

Question 46

Which of the following statements is correct?

  1. AOption (a)

    In sexual mode of reproduction, germ-cells from one individual have to join together.

  2. BOption (b)

    At maturity, the rate of general body growth in humans begins to slow down. 

  3. COption (c)

    At maturity, the rate of general body growth in humans begins to get faster. 

  4. DOption (d)

    At maturity, the reproductive tissue stops to mature in humans.

View answer & explanation

Correct answer

Answer: (b)B.

At maturity, the rate of general body growth in humans begins to slow down. 

Why this answer is correct

The correct answer is Option 2.

Key Points

  • At maturity, the rate of general body growth in humans begins to slow down.
  • This slowing down is primarily due to the completion of puberty and the end of the adolescent growth spurt.
  • During puberty, the body undergoes rapid growth and changes, including the development of secondary sexual characteristics.
  • Once maturity is reached, most individuals have achieved their maximum height, and the rate of growth in other body tissues also slows down significantly.

Additional Information

  • Germ Cells: These are reproductive cells (sperm in males and eggs in females) that combine during sexual reproduction to form a new organism.
  • Puberty: A developmental period in humans and other animals during which physical growth and sexual maturation occur rapidly.
  • Adolescent Growth Spurt: A period of rapid physical growth and development during puberty, typically resulting in a significant increase in height.
  • Secondary Sexual Characteristics: Physical traits that differentiate the sexes, such as breast development in females and facial hair in males, which develop during puberty.
  • Reproductive Maturity: The stage in life when an individual is fully capable of reproduction, typically marked by the completion of puberty and the development of functional reproductive organs.

Question 47

Manju ranked 17th from the bottom and 8th from the top in his class. How many students are there in his class?

  1. AOption (a)

    22

  2. BOption (b)

    24

  3. COption (c)

    23

  4. DOption (d)

    25

View answer & explanation

Correct answer

Answer: (b)B.

24

Why this answer is correct

Given:

Manju ranked 8th from the top and 17nd from the bottom in his class.

Total students = Rank from Top + Rank from Bottom − 1

= 8 + 17− 1

= 25 − 1

= 24

Thus, total 24 students are there in the class.

Hence, the correct answer is "Option 2".

Question 48

A dishonest shopkeeper pretends to sell his goods at cost price, but uses a false weights and gains 1119%11\frac{1}{9}\%. For a weight of a kg, he uses:

  1. AOption (a)

    900 gm weight

  2. BOption (b)

    850 gm weight

  3. COption (c)

    950 gm weight

  4. DOption (d)

    875 gm weight

View answer & explanation

Correct answer

Answer: (a)A.

900 gm weight

Why this answer is correct

Shortcut Trick

Profit % = 11(1/9)% = 1/9 in fractional form.

This means for every 9 units of False Weight, the profit is 1 unit.

Ratio of True Weight to False Weight = (9 + 1) : 9 = 10 : 9.

Given 10 units = 1000 gm (1 kg).

⇒ 1 unit = 100 gm.

⇒ 9 units = 9 × 100 gm = 900 gm.

∴ The correct answer is 900 gm weight.

Alternate Method

Given:

Profit percentage = 11(1/9)% = 100/9%

True Weight = 1 kg = 1000 gm

Formula Used:

Profit % = [ (True Weight − False Weight) ÷ False Weight ] × 100

Calculations:

Let the False Weight used by the shopkeeper be x gm.

⇒ 100/9 = [ (1000 − x) ÷ x ] × 100

⇒ 1/9 = (1000 − x) ÷ x

⇒ x = 9 × (1000 − x)

⇒ x = 9000 − 9x

⇒ 10x = 9000

⇒ x = 900 gm

∴ The correct answer is 900 gm weight.

Additional Information

Dishonest Dealer Concept

When a dealer sells at Cost Price but uses less weight, the Profit % is always calculated on the False Weight (what he actually gives).

Case of Dual Profit

If a dealer marks up the price by a% and also uses a false weight giving b% less, the Total Profit % = [ (100 + a) / (100 − b) × 100 ] − 100.

Successive Percentage Method

For cheating while buying (x%) and selling (y%), the Net Profit % can be calculated using the formula: x + y + (xy/100).

Question 49

MPLO is related to RUQT in a certain way based on the English alphabetical order. In the same way, ILHK is related to NQMP. To which of the following options is FIEH related, following the same logic?

  1. AOption (a)

    NKMJ

  2. BOption (b)

    KNMJ

  3. COption (c)

    KNJM

  4. DOption (d)

    NKJM

View answer & explanation

Correct answer

Answer: (c)C.

KNJM

Why this answer is correct

Logic followed here is,

Logic: Every letter is increased by 5.

Given,

MPLO is related to RUQT

For, ILHK is related to NQMP.

Similarly for FIEH is related to KNJM.

Hence the correct answer is "Option 3"

Question 50

Protein digesting enzyme pepsin is secreted in the:

  1. AOption (a)

    ileum

  2. BOption (b)

    stomach

  3. COption (c)

    mouth

  4. DOption (d)

    duodenum

View answer & explanation

Correct answer

Answer: (b)B.

stomach

Why this answer is correct

The correct answer is stomach.

Key Points

  • Pepsin is a proteolytic enzyme that is secreted by the chief cells in the stomach lining.
  • The secretion is initially in the form of an inactive precursor called pepsinogen.
  • Pepsinogen is converted to active pepsin in the acidic environment of the stomach, primarily due to the action of hydrochloric acid (HCl).
  • Pepsin plays a crucial role in the digestion of proteins, breaking them down into smaller peptides.
  • The pH level in the stomach, which ranges from 1.5 to 3.5, is optimal for pepsin activity.

Additional Information

  • Chief Cells:
  • These are cells in the stomach lining that secrete pepsinogen and gastric lipase.
  • Chief cells are also known as zymogenic cells.
  • Hydrochloric Acid (HCl):
  • Produced by parietal cells in the stomach lining.
  • Creates an acidic environment, which is necessary for the conversion of pepsinogen to pepsin.
  • Gastric Mucosa:
  • The mucous membrane layer of the stomach, which contains the glands and the gastric pits.
  • Responsible for the secretion of gastric juices, including pepsinogen and HCl.
  • Protein Digestion:
  • Starts in the stomach with the action of pepsin.
  • Continues in the small intestine with the help of other proteolytic enzymes like trypsin and chymotrypsin.

Question 51

In a circuit, suppose the three resistors having the values 5, 10, 20 N are connected in parallel; then equivalent resistance of the circuit will be ______.

  1. AOption (a)

    35 Ω

  2. BOption (b)

    20 Ω

  3. COption (c)

    407\frac{40}{7} Ω

  4. DOption (d)

    207\frac{20}{7} Ω

View answer & explanation

Correct answer

Answer: (d)D.

207\frac{20}{7} Ω

Why this answer is correct

The correct answer is (20)/(7) Ω.

Key Points

  • When resistors are connected in parallel, the reciprocal of the equivalent resistance (Req) is the sum of the reciprocals of the individual resistances.
  • The formula used is: 1/Req = 1/R1 + 1/R2 + 1/R3.
  • For resistors with values 5Ω, 10Ω, and 20Ω, the calculation is: 1/Req = 1/5 + 1/10 + 1/20.
  • Solving the equation: 1/Req = (4 + 2 + 1)/20 = 7/20, thus Req = 20/7 Ω.

Additional Information

  • Series vs. Parallel Circuits:
  • In a series circuit, resistors are connected end-to-end, and the total resistance is the sum of individual resistances.
  • In a parallel circuit, resistors are connected across the same two points, and the total resistance is less than the smallest individual resistance.
  • Ohm's Law:
  • Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
  • The formula is V = IR, where V is voltage, I is current, and R is resistance.
  • Applications of Parallel Circuits:
  • Parallel circuits are commonly used in household wiring, allowing multiple devices to operate independently.
  • They ensure that if one component fails, the rest of the circuit can still function.
  • Calculating Total Resistance:
  • For multiple resistors in parallel, always use the reciprocal formula to find the total or equivalent resistance.
  • This method ensures accurate calculation and understanding of how current divides among different branches.

Question 52

If the area of an equilateral triangle is 16√3 sq cm, then the length of each side of the triangle is: 

  1. AOption (a)

    10 cm

  2. BOption (b)

    8 cm

  3. COption (c)

    12 cm

  4. DOption (d)

    5 cm

View answer & explanation

Correct answer

Answer: (b)B.

8 cm

Why this answer is correct

Shortcut Trick

For an equilateral triangle, the relationship between Area and side (a) is: Area = (√3/4) × a2.

Given Area = 16√3, we have 16√3 = (√3/4) × a2.

Eliminate √3 from both sides: 16 = a2/4 ⇒ a2 = 64.

Taking square root: a = 8 cm.

∴ The correct answer is 8 cm.

Alternate Method

Given:

Area of equilateral triangle = 16√3 cm2

Formula Used:

Area = (√3/4) × (side)2

Calculations:

⇒ 16√3 = (√3/4) × a2

⇒ 16 = a2 / 4

⇒ a2 = 16 × 4

⇒ a2 = 64

⇒ a = √64

⇒ a = 8 cm

∴ The correct answer is 8 cm.

Additional Information

Height of Equilateral Triangle

The altitude or height (h) of an equilateral triangle is given by h = (√3/2) × a.

Perimeter of Equilateral Triangle

Since all three sides are equal, the perimeter (P) = 3 × a.

Inradius and Circumradius

Inradius (r) = a / (2√3) and Circumradius (R) = a / √3. Note that R = 2r.

Question 53

In which of the pairs of the following numbers is none of the two numbers a prime number, but the two numbers are co-primes?

  1. AOption (a)

    (21, 35)

  2. BOption (b)

    (19, 27)

  3. COption (c)

    (11, 17)

  4. DOption (d)

    (8, 25)

View answer & explanation

Correct answer

Answer: (d)D.

(8, 25)

Why this answer is correct

Shortcut Trick

Check each pair for two conditions: 1. Both numbers must be composite (not prime). 2. Their HCF must be 1 (co-prime).

Option 1: (21, 35) → Both composite, but HCF = 7.

Option 2: (19, 27) → 19 is a prime number.

Option 3: (11, 17) → Both are prime numbers.

Option 4: (8, 25) → Both are composite and HCF = 1.

∴ The correct answer is (8, 25).

Alternate Method

Given: Pairs of numbers to check for non-prime and co-prime status.

Definitions: Prime Number has exactly 2 factors. Co-prime numbers have an HCF of 1.

⇒ Case 1: (21, 35) → Factors of 21: 1, 3, 7, 21; Factors of 35: 1, 5, 7, 35. HCF = 7 (Not co-prime).

⇒ Case 2: (19, 27) → 19 is a Prime Number (Violates first condition).

⇒ Case 3: (11, 17) → Both 11 and 17 are Prime Numbers (Violates first condition).

⇒ Case 4: (8, 25) → Factors of 8: 1, 2, 4, 8; Factors of 25: 1, 5, 25. Both are Composite and HCF = 1.

∴ The correct answer is (8, 25).

Additional Information

Co-prime Numbers

Two numbers are said to be co-prime if their Greatest Common Divisor (GCD) or HCF is 1. They do not need to be prime numbers themselves.

Composite Numbers

Numbers that have more than two factors are composite. 1 is neither prime nor composite.

Twin Primes

A pair of prime numbers that have a difference of 2, such as (11, 13) or (17, 19).

Question 54

Honey is produced by the honeybee. So, the honeybee is a ______.

  1. AOption (a)

    secondary consumer  

  2. BOption (b)

    primary consumer  

  3. COption (c)

    producer 

  4. DOption (d)

    Decomposer 

View answer & explanation

Correct answer

Answer: (b)B.

primary consumer  

Why this answer is correct

The correct answer is primary consumer.

Key Points

  • Honeybees collect nectar from flowers, which makes them primary consumers as they directly feed on producers (plants).
  • Primary consumers are organisms that consume producers (plants) for energy.
  • In the food chain, primary consumers are typically herbivores or omnivores.
  • Honeybees play a crucial role in pollination, which supports the growth of plants and the ecosystem.

Additional Information

  • Producers: Organisms that produce their own food using sunlight, water, and carbon dioxide (e.g., plants, algae).
  • Primary Consumers: Organisms that feed directly on producers (e.g., herbivores like cows, and insects like honeybees).
  • Secondary Consumers: Organisms that consume primary consumers (e.g., carnivores like lions, and omnivores like humans).
  • Decomposers: Organisms that break down dead or decaying organisms, recycling nutrients back into the ecosystem (e.g., fungi, bacteria).
  • Honeybees contribute to biodiversity by aiding in plant reproduction through the process of pollination.

Question 55

Which of the following is NOT a sign of sexual maturity in girls? 

  1. AOption (a)

    Cracking of voice 

  2. BOption (b)

    Oily skin 

  3. COption (c)

    Increase in breast size 

  4. DOption (d)

    Menstruation  

View answer & explanation

Correct answer

Answer: (a)A.

Cracking of voice 

Why this answer is correct

The correct answer is 1) Cracking of voice.

Key Points

  • Cracking of voice is typically associated with puberty in boys, not girls.
  • During puberty, boys experience a deepening of the voice due to the growth of the larynx and lengthening of the vocal cords.
  • Girls do not usually experience a significant change in voice pitch during puberty.
  • The voice changes in girls during puberty are generally more subtle and less pronounced compared to boys.

Additional Information

  • Oily Skin: An increase in the production of sebum due to hormonal changes often leads to oily skin during puberty in both boys and girls.
  • Increase in Breast Size: One of the primary signs of sexual maturity in girls is the development and growth of breasts.
  • Menstruation: The onset of menstruation is a key indicator of sexual maturity in girls, marking the beginning of reproductive capability.
  • Puberty in Girls: Typically occurs between the ages of 8 and 13 and includes physical changes such as the development of secondary sexual characteristics and the onset of menstruation.
  • Hormonal Changes: Puberty is driven by hormonal changes, primarily the increase in estrogen in girls, which leads to the development of secondary sexual characteristics.

Question 56

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)

    TY-VA 

  2. BOption (b)

    DI-FK

  3. COption (c)

    BG-DI 

  4. DOption (d)

    XB-YC 

View answer & explanation

Correct answer

Answer: (d)D.

XB-YC 

Why this answer is correct

Logic follows here is that the first letter and the second letter are increased by 2.

Option 1) TY-VA 

Option 2) DI-FK

Option 3) BG-DI 

Option 4) XB-YC 

Does not follow the same logic.

Hence the correct answer is "Option 4"

Question 57

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

  1. AOption (a)

    B

  2. BOption (b)

    Q

  3. COption (c)

    R

  4. DOption (d)

    E

View answer & explanation

Correct answer

Answer: (a)A.

B

Why this answer is correct

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

Only three people sit between R and E when counted from the left of R.

Only two people sit between E and Q.

B sits third to the right of Q.

F sits to the immediate left of P

And A sits at the remaining place.

 So B sits to the immediate right of A.

Hence the correct answer is "Option 1"

Question 58

In January 2024, what significant milestone did the Indian Air Force (IAF) achieve in terms of landing operations?

  1. AOption (a)

     First deployment of the Garud Special Forces using a C-130J Super Hercules

  2. BOption (b)

    First operation of a C-130J Super Hercules at the world's highest airstrip

  3. COption (c)

    First successful night landing at the Kargil airfield with a C-130J Super Hercules

  4. DOption (d)

    First landing of a C-130J Super Hercules aircraft at Daulat Beg Oldie

View answer & explanation

Correct answer

Answer: (c)C.

First successful night landing at the Kargil airfield with a C-130J Super Hercules

Why this answer is correct

The correct answer is First successful night landing at the Kargil airfield with a C-130J Super Hercules.

Key Points

  • In January 2024, the Indian Air Force achieved a significant milestone by conducting the first successful night landing at the Kargil airfield using a C-130J Super Hercules.
  • This operation demonstrated the IAF's enhanced night-time operational capabilities in high-altitude and tough terrains.
  • The C-130J Super Hercules is known for its versatility, capable of landing on short and unpaved airstrips, making it ideal for such challenging missions.
  • This achievement marks a strategic enhancement, ensuring better logistical and tactical support in the region, especially in times of conflict or emergency.

Additional Information

  • C-130J Super Hercules:
  • A military transport aircraft known for its versatility and reliability.
  • Capable of performing a variety of missions, including transport, medevac, and aerial refueling.
  • Equipped with advanced avionics and propulsion systems to handle short and unpaved runways.
  • Kargil Airfield:
  • Located in the challenging terrain of the Himalayan region.
  • Strategically important due to its proximity to the Line of Control (LoC).
  • Used primarily for transport and logistical purposes during the Kargil War in 1999.
  • Night Operations:
  • Require advanced navigation and landing systems.
  • Enhance the operational readiness of the air force.
  • Critical for surprise and stealth missions.
  • Indian Air Force (IAF):
  • The air arm of the Indian Armed Forces.
  • Responsible for securing Indian airspace and conducting aerial warfare.
  • Continuously upgrading its fleet and capabilities to handle modern-day threats and challenges.

Question 59

If each vowel in the word ARTICULATE is changed to the letter immediately following it in the English alphabetical order and each consonant is changed to the letter immediately preceding it in the English alphabetical order, then which of the following letters will appear more than twice in the group of letters thus formed? 

  1. AOption (a)

    J

  2. BOption (b)

    K

  3. COption (c)

    S

  4. DOption (d)

    B

View answer & explanation

Correct answer

Answer: (d)D.

B

Why this answer is correct

Given:

Word: ARTICULATE

Rule: Vowels -> next letter, Consonants -> previous letter

Apply the rule to each letter:

  • A -> B
  • R -> Q
  • T -> S
  • I -> J
  • C -> B
  • U -> V
  • L -> K
  • A -> B
  • T -> S
  • E -> F

Resulting letters: B Q S J B V K B S F

B appears 3 times.

Conclusion:

Only the letter B appears more than twice.

Therefore, the correct answer is option 4) B.

Question 60

Study the following table and answer the question.

Number of candidates appeared and qualified in a competitive examination from different states over the years.  

StateYear
20202021
AppearedQualifiedAppearedQualified
A500100600150
B600200800250
C40050500100
D3006040080
<br>

For which state did the percentage of students qualified did NOT change from 2020 to 2021?

  1. AOption (a)

    C

  2. BOption (b)

    D

  3. COption (c)

    A

  4. DOption (d)

    B

View answer & explanation

Correct answer

Answer: (b)B.

D

Why this answer is correct

Formula used:

Percentage of students qualified = (Qualified / Appeared) × 100

Calculations:

For State A:

2020: (100 / 500) × 100 = 20%

2021: (150 / 600) × 100 = 25%

For State B:

2020: (200 / 600) × 100 = 33.33%

2021: (250 / 800) × 100 = 31.25%

For State C:

2020: (50 / 400) × 100 = 12.5%

2021: (100 / 500) × 100 = 20%

For State D:

2020: (60 / 300) × 100 = 20%

2021: (80 / 400) × 100 = 20%

The percentage of students qualified did NOT change from 2020 to 2021 is from state D.

∴ The correct answer is option 2.

Question 61

In a certain code language, ‘WHELP’ is coded as ‘24681' and ‘HELPS’ is coded as ‘12674'. What is the code for “W' in the given code language? 

  1. AOption (a)

    2

  2. BOption (b)

    4

  3. COption (c)

    8

  4. DOption (d)

    1

View answer & explanation

Correct answer

Answer: (c)C.

8

Why this answer is correct

Logic followed here is

Logic : HELP is common in both the language and 2 4 6 1 is common in both the code.

So, code for W is 8.

Hence the correct answer is option (3).

Question 62

If the mass of a football is 3 kg, then what would be its weight on the earth? (Given, = 9.8 m s-2)

  1. AOption (a)

    30.5 N

  2. BOption (b)

    35 N

  3. COption (c)

    25 N

  4. DOption (d)

    29.4 N

View answer & explanation

Correct answer

Answer: (d)D.

29.4 N

Why this answer is correct

The correct answer is 29.4 N.

Key Points

  • The mass of the football is given as 3 kg.
  • The acceleration due to gravity on Earth is 9.8 m/s².
  • Weight is calculated using the formula: Weight (W) = Mass (m) × Acceleration due to gravity (g).
  • Substituting the values, W = 3 kg × 9.8 m/s².
  • The weight of the football on Earth is 29.4 N.

Additional Information

  • Mass and Weight:
  • Mass is a measure of the amount of matter in an object, typically measured in kilograms (kg).
  • Weight is the force exerted by gravity on an object, measured in Newtons (N).
  • Gravitational Force:
  • Gravitational force is the attractive force between two masses.
  • On Earth, this force is quantified as 9.8 m/s².
  • Formula for Weight:
  • The formula to calculate weight is W = m × g.
  • Here, W represents weight, m represents mass, and g represents the gravitational force.
  • Importance of Gravity:
  • Gravity keeps planets in orbit around the sun.
  • It gives weight to physical objects and is responsible for the free fall of objects.

Question 63

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.)

(4, 12, 48)

(7, 21, 84)

  1. AOption (a)

    (5, 45, 180) 

  2. BOption (b)

    (15, 25, 180) 

  3. COption (c)

    (15, 45, 180) 

  4. DOption (d)

    (15, 45, 170) 

View answer & explanation

Correct answer

Answer: (c)C.

(15, 45, 180) 

Why this answer is correct

Given:

Sets: (4, 12, 48) and (7, 21, 84)

Formula: First number × 3 = Second number

Formula: Second number × 4 = Third number

Given (4, 12, 48):

4 × 3 = 12

12 × 4 = 48

For (7, 21, 84):

7 × 3 = 21

21 × 4 = 84

Option 1) (5, 45, 180):

5 × 3 = 15 (Does not match 45)

45 × 4 = 180 (Matches the third number but second number does not match)

Option 2) (15, 25, 180):

15 × 3 = 45 (Does not match 25)

25 × 4 = 100 (Does not match 180)

Option 3) (15, 45, 180):

15 × 3 = 45

45 × 4 = 180

Only Option 3 satisfies both conditions.

Option 4) (15, 45, 170):

15 × 3 = 45

45 × 4 = 180 (Does not match 170)

Therefore, the correct answer is option 3) (15, 45, 180).

Question 64

A pipe can fill a tank in 12 hours. Another pipe can empty the filled tank in 28 hours. If both the pipes are opened simultaneously, then the time (in hours) in which the tank will be one-third filled, is:

  1. AOption (a)

    21

  2. BOption (b)

    28

  3. COption (c)

    14

  4. DOption (d)

    7

View answer & explanation

Correct answer

Answer: (d)D.

7

Why this answer is correct

Given:

Pipe 1 fills the tank in 12 hours.

Pipe 2 empties the tank in 28 hours.

Formula used:

Work done = LCM of time taken

Efficiency = Total work / Time

Calculation:

LCM of 12 and 28 = 84

Let the total capacity of the tank be 84 units.

Efficiency of Pipe 1 (filling) = 84 / 12 = 7 units/hour

Efficiency of Pipe 2 (emptying) = 84 / 28 = 3 units/hour

Net efficiency when both pipes are open = 7 - 3 = 4 units/hour

One-third capacity of the tank = 84 / 3 = 28 units

Time taken to fill one-third of the tank = 28 / 4 = 7 hours

∴ The time taken to fill one-third of the tank is 7 hours.

Question 65

Which of the following is produced when acid reacts with metals? 

  1. AOption (a)

    Salt and hydrogen gas 

  2. BOption (b)

    Only Salt 

  3. COption (c)

    Salt and water 

  4. DOption (d)

    Only Hydrogen gas 

View answer & explanation

Correct answer

Answer: (a)A.

Salt and hydrogen gas 

Why this answer is correct

The correct answer is Salt and hydrogen gas.

Key Points

  • When acids react with metals, they produce a salt and hydrogen gas.
  • This is a typical single displacement reaction where the metal displaces hydrogen from the acid.
  • For example, when zinc (Zn) reacts with hydrochloric acid (HCl), it forms zinc chloride (ZnCl₂) and hydrogen gas (H₂).
  • The general equation for this type of reaction is: Metal + Acid → Salt + Hydrogen gas.
  • Common metals that react with acids include zinc, magnesium, and iron.

Additional Information

  • Oxidation-Reduction Reaction: In the reaction between acids and metals, the metal undergoes oxidation (loses electrons) and hydrogen ions (H⁺) from the acid are reduced (gain electrons).
  • Reactivity Series: Not all metals react with acids. The reactivity series of metals determines which metals will react with acids to produce hydrogen gas.
  • Safety Precautions: The reaction between metals and acids can be vigorous and produce hydrogen gas, which is highly flammable. Proper safety measures should be taken.
  • Applications: This type of reaction is utilized in various industrial processes including the production of hydrogen gas and in metal refining.

Question 66

If an object is placed in front of a concave mirror at a distance of 20 cm and the image is formed on the same side at a distance of 40 cm, then the magnification of the mirror will be: 

  1. AOption (a)

    -0.4

  2. BOption (b)

    +0.4

  3. COption (c)

    +2.0

  4. DOption (d)

    -2.0

View answer & explanation

Correct answer

Answer: (d)D.

-2.0

Why this answer is correct

The correct answer is -2.

Key Points

  • The magnification (m) of a mirror is calculated using the formula: m = -v/u, where 'v' is the image distance and 'u' is the object distance.
  • Here, the object distance (u) is -20 cm (negative as it is in front of the mirror) and the image distance (v) is -40 cm (negative as it is a real image formed on the same side as the object).
  • Substituting the values, m = -(-40 cm) / (-20 cm) = 40 / 20 = 2.0.
  • Since the image is real and inverted, the magnification will be negative: m = -2.0.
  • Thus, the correct magnification of the mirror is -2.0, which corresponds to option 4.

Additional Information

  • Concave Mirrors:
  • Concave mirrors are spherical mirrors that curve inward, resembling a portion of the interior of a sphere.
  • They are known to converge light rays to a focal point, making them useful in applications like telescopes and shaving mirrors.
  • Mirror Formula:
  • The mirror formula relates object distance (u), image distance (v), and focal length (f) through the equation: 1/f = 1/u + 1/v.
  • Magnification:
  • Magnification (m) indicates how much larger or smaller the image is compared to the object.
  • For mirrors, it is calculated as the ratio of the image height to the object height or -v/u for distances.
  • Real vs. Virtual Images:
  • Real images are formed when light rays converge and can be projected on a screen; they are inverted.
  • Virtual images occur when light rays only appear to diverge from a point; they are upright.

Question 67

Which of the following products is NOT formed when electricity is passed through an aqueous solution of sodium chloride? 

  1. AOption (a)

    Hydrogen gas 

  2. BOption (b)

    Sodium hydroxide 

  3. COption (c)

    Chlorine gas  

  4. DOption (d)

    Oxygen gas  

View answer & explanation

Correct answer

Answer: (d)D.

Oxygen gas  

Why this answer is correct

The correct answer is Oxygen gas.

Key Points

  • When electricity is passed through an aqueous solution of sodium chloride (brine), the main products formed are hydrogen gas, chlorine gas, and sodium hydroxide.
  • Hydrogen gas is produced at the cathode due to the reduction of water molecules.
  • Chlorine gas is generated at the anode by the oxidation of chloride ions.
  • Sodium hydroxide is formed in the solution as a result of the ions remaining after the electrolysis process.
  • Oxygen gas is not produced in this process as the primary reactions involve the decomposition of water and chloride ions, not oxygen.

Additional Information

  • Electrolysis:
  • Electrolysis is a chemical process that uses electric current to drive a non-spontaneous chemical reaction.
  • In the electrolysis of brine, the solution conducts electricity due to the presence of ions.
  • Brine Solution:
  • Brine is a high-concentration solution of salt (sodium chloride) in water.
  • It is commonly used in the chlor-alkali industry for the production of chlorine, hydrogen, and sodium hydroxide.
  • Cathode and Anode Reactions:
  • At the cathode: 2H2O + 2e- → H2 + 2OH-
  • At the anode: 2Cl- → Cl2 + 2e-
  • Industrial Applications:
  • The products of brine electrolysis are used in various industries: chlorine for disinfectants and PVC, hydrogen for fuel, and sodium hydroxide for soap and paper manufacturing.

Question 68

Who among the following scientists was the first to use a glass prism to discover the spectrum of sunlight? 

  1. AOption (a)

    Sir Isaac Newton 

  2. BOption (b)

    Albert Einstein 

  3. COption (c)

    Prof CV Raman 

  4. DOption (d)

    Archimedes  

View answer & explanation

Correct answer

Answer: (a)A.

Sir Isaac Newton 

Why this answer is correct

The correct answer is Sir Isaac Newton.

Key Points

  • Sir Isaac Newton was the first scientist to use a glass prism to discover the spectrum of sunlight.
  • He conducted the experiment in 1666, demonstrating that white light is composed of different colors.
  • Newton's work laid the foundation for the field of optics.
  • He published his findings in the book "Opticks" in 1704.

Additional Information

  • Prism:
  • A prism is a transparent optical element with flat, polished surfaces that refract light.
  • Prisms can be used to break light up into its constituent spectral colors (the colors of the rainbow).
  • Optics:
  • Optics is the branch of physics that studies the behavior and properties of light.
  • It includes the study of reflection, refraction, dispersion, and the interaction of light with matter.
  • White Light:
  • White light is a combination of all colors in the visible spectrum.
  • When passed through a prism, white light is dispersed into its component colors.
  • Newton's Contributions:
  • Isaac Newton made significant contributions to mathematics, physics, and astronomy.
  • He is also known for his laws of motion and universal gravitation.

Question 69

To promote the dialogue of traditions, national values and cultures, India participated in the BRICS Literature Forum 2024 in ______.

  1. AOption (a)

    Nepal

  2. BOption (b)

    Russia

  3. COption (c)

    Bhutan

  4. DOption (d)

    China

View answer & explanation

Correct answer

Answer: (b)B.

Russia

Why this answer is correct

The correct answer is Russia.

Key Points

  • India participated in the BRICS Literature Forum 2024 held in Russia to promote the dialogue of traditions, national values, and cultures among BRICS nations.
  • The BRICS Literature Forum is a significant event that brings together writers, poets, and literary figures from BRICS countries to discuss and share their cultural and literary heritage.
  • Russia hosted the 2024 forum, showcasing its commitment to fostering cultural cooperation and mutual understanding among BRICS countries.
  • The forum included various literary discussions, workshops, and cultural performances aimed at enhancing the literary ties between the member countries.

Additional Information

  • BRICS:
  • BRICS is an acronym for five major emerging economies: Brazil, Russia, India, China, and South Africa.
  • These countries are known for their significant influence on regional and global affairs.
  • The BRICS grouping aims to promote peace, security, and development in the global economy.
  • Cultural Exchange Programs:
  • Cultural exchange programs are initiatives designed to foster mutual understanding and cooperation between different countries.
  • Such programs often include exchanges in the fields of arts, literature, education, and sports.
  • Literary Forums:
  • Literary forums are platforms where writers, poets, and literary critics gather to discuss and promote literature.
  • These forums play a crucial role in preserving and promoting cultural heritage and literary traditions.
  • BRICS Cultural Cooperation:
  • The BRICS countries have established various cultural cooperation initiatives to enhance mutual understanding and cultural exchange.
  • These initiatives include film festivals, art exhibitions, and literary forums.

Question 70

The area (in cm2) of an equilateral triangle whose altitude from vertex is 12 cm, is:

  1. AOption (a)

    27√3

  2. BOption (b)

    48√3

  3. COption (c)

    932\frac{9\sqrt3}{2}

  4. DOption (d)

    934\frac{9\sqrt3}{4}

View answer & explanation

Correct answer

Answer: (b)B.

48√3

Why this answer is correct

Shortcut Trick

For an equilateral triangle, the relationship between Area and Altitude (h) is given by:

Area = h2 ÷ √3

⇒ Area = 122 ÷ √3 = 144 ÷ √3

⇒ Area = (144 × √3) ÷ 3 = 48√3 cm2

∴ The correct answer is 48√3 cm2.

Alternate Method

Given: Altitude (h) of the equilateral triangle = 12 cm.

Formula Used:

  1. Altitude (h) = (√3 ÷ 2) × side (a)
  2. Area = (√3 ÷ 4) × a2

Calculations:

⇒ 12 = (√3 ÷ 2) × a

⇒ a = 24 ÷ √3 = 8√3 cm

⇒ Area = (√3 ÷ 4) × (8√3)2

⇒ Area = (√3 ÷ 4) × (64 × 3)

⇒ Area = (√3 ÷ 4) × 192

⇒ Area = 48√3 cm2

∴ The correct answer is 48√3 cm2.

Additional Information

Properties of Equilateral Triangle

All three sides are equal, and each interior angle is 60°.

Inradius and Circumradius

Inradius (r) = a ÷ (2√3) and Circumradius (R) = a ÷ √3.

Perimeter of Equilateral Triangle

Perimeter = 3 × side (a).

Question 71

Seven people, A, B, C, L, X, Y and Z are sitting in a row, facing north. Only three people sit between B and L. C sits to the immediate left of L. No one sits to the right of Y. Only two people sit between Y and C. Z sits to the immediate right of A.

How many people sit between X and Z?

  1. AOption (a)

    One

  2. BOption (b)

    Four

  3. COption (c)

    Three

  4. DOption (d)

    Two

View answer & explanation

Correct answer

Answer: (d)D.

Two

Why this answer is correct

Given, Seven people, A, B, C, L, X, Y and Z are sitting in a row, facing north.

No one sits to the right of Y.

Only two people sit between Y and C.

Only three people sit between B and L.

C sits to the immediate left of L.

Z sits to the immediate right of A.

X sits at the remaining place.

So 2 people sit between X and Z.

Hence the correct answer is "Option 4"

Question 72

If x+1x=6\rm x + \frac{1}{x}=6, then x2+1x2=?\rm x^2 + \frac{1}{x^2}=?

  1. AOption (a)

    32

  2. BOption (b)

    34

  3. COption (c)

    38

  4. DOption (d)

    36

View answer & explanation

Correct answer

Answer: (b)B.

34

Why this answer is correct

Shortcut Trick

For any expression of the form x + 1/x = k, the value of x2 + 1/x2 is given by the direct formula k2 − 2.

Given k = 6.

⇒ x2 + 1/x2 = 62 − 2

⇒ 36 − 2 = 34

∴ The correct answer is 34.

Alternate Method

Given: x + 1/x = 6

Formula Used: (a + b)2 = a2 + b2 + 2ab

Squaring both sides of the given equation:

⇒ (x + 1/x)2 = 62

⇒ x2 + (1/x)2 + 2 × x × (1/x) = 36

⇒ x2 + 1/x2 + 2 = 36

⇒ x2 + 1/x2 = 36 − 2

⇒ x2 + 1/x2 = 34

∴ The correct answer is 34.

Additional Information

Higher Power Relation (Cube)

If x + 1/x = k, then x3 + 1/x3 = k3 − 3k.

Negative Sign Identity

If x − 1/x = k, then x2 + 1/x2 = k2 + 2.

Fourth Power Relation

To find x4 + 1/x4, square the result of (x2 + 1/x2) and subtract 2.

Question 73

The rigid outer covering present outside the plasma membrane in plants is called the: 

  1. AOption (a)

    cell envelope

  2. BOption (b)

    selectively permeable membrane

  3. COption (c)

    cell wall

  4. DOption (d)

    nuclear membrane

View answer & explanation

Correct answer

Answer: (c)C.

cell wall

Why this answer is correct

The correct answer is cell wall.

Key Points

  • The cell wall is a rigid layer that is found outside the plasma membrane in plant cells, bacteria, fungi, and some algae.
  • In plants, the cell wall is primarily composed of cellulose, hemicellulose, and pectin.
  • The cell wall provides structural support and protection, and it also acts as a filtering mechanism.
  • It is crucial for maintaining the shape of the plant cell and preventing excessive water intake through osmosis.

Additional Information

  • Plasma Membrane:
  • A selectively permeable membrane that regulates the entry and exit of substances in and out of the cell.
  • Composed of a phospholipid bilayer with embedded proteins.
  • Cell Envelope:
  • In bacteria, the cell envelope includes the plasma membrane, cell wall, and sometimes an outer membrane.
  • Provides structural integrity and protection from environmental stress.
  • Nuclear Membrane:
  • A double membrane that encloses the nucleus in eukaryotic cells.
  • Contains nuclear pores that allow the transport of molecules between the nucleus and cytoplasm.
  • Composition of Plant Cell Walls:
  • Primary Cell Wall: Thin and flexible, made of cellulose, hemicellulose, and pectin.
  • Secondary Cell Wall: Thicker and more rigid, contains lignin in addition to cellulose and hemicellulose.

Question 74

Which team of Indian Space Research Organisation (ISRO) won the Vigyan Team award in 2024?

  1. AOption (a)

    Chandrayaan-2 Team

  2. BOption (b)

    XPoSat Team

  3. COption (c)

    Aditya-L1 Team

  4. DOption (d)

    Chandrayaan-3 Team

View answer & explanation

Correct answer

Answer: (d)D.

Chandrayaan-3 Team

Why this answer is correct

The correct answer is Chandrayaan-3 Team.

Key Points

  • The Chandrayaan-3 Team of ISRO was awarded the Vigyan Team award in 2024.
  • Chandrayaan-3 is the third lunar exploration mission by the Indian Space Research Organisation (ISRO).
  • The mission aims to demonstrate the capability of soft-landing on the lunar surface and operate a rover.
  • Chandrayaan-3 was built upon the experience gained from the Chandrayaan-2 mission.

Additional Information

  • Chandrayaan-2
  • Chandrayaan-2 was launched on 22 July 2019.
  • It aimed to explore the south pole of the Moon.
  • The mission included an orbiter, a lander named Vikram, and a rover named Pragyan.
  • Aditya-L1 Mission
  • Aditya-L1 is ISRO's mission to study the Sun.
  • The mission aims to understand the dynamic processes of the Sun and its impact on the space environment.
  • XPoSat Mission
  • XPoSat (X-ray Polarimeter Satellite) is a dedicated mission to study cosmic X-ray sources.
  • It aims to observe the polarization of X-rays from various sources like pulsars and black hole binaries.
  • ISRO's Achievements
  • ISRO has successfully launched missions like Mars Orbiter Mission (Mangalyaan) and various communication satellites.
  • It has made significant contributions to space exploration and satellite technology.

Question 75

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

194, 249, 199, 244, 204,?

  1. AOption (a)

    239

  2. BOption (b)

    219

  3. COption (c)

    224

  4. DOption (d)

    234

View answer & explanation

Correct answer

Answer: (a)A.

239

Why this answer is correct

Given

194, 249, 199, 244, 204,?

Logic follows here is,

Logic 

So, next number is 239.

Hence the correct answer is "Option 1"

Question 76

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

ACY, MOK, YAW, KMI, ?

  1. AOption (a)

    WZU

  2. BOption (b)

    WYU

  3. COption (c)

    WYV

  4. DOption (d)

    WZV

View answer & explanation

Correct answer

Answer: (b)B.

WYU

Why this answer is correct

Logic followed here is,

Hence the correct answer is "Option 2"

Question 77

Which of the following statements is true? 

  1. AOption (a)

    The weight of an object is the power with which it is attracted towards the earth. 

  2. BOption (b)

    The weight of an object is constant and does not change from place to place. 

  3. COption (c)

    The mass of an object is constant and does not change from place to place. 

  4. DOption (d)

    The weight is equal to the product of velocity and acceleration due to gravity. 

View answer & explanation

Correct answer

Answer: (c)C.

The mass of an object is constant and does not change from place to place. 

Why this answer is correct

The correct answer is 3) The mass of an object is constant and does not change from place to place.

Key Points

  • Mass is a fundamental property of an object that does not change regardless of location.
  • The mass of an object is measured in kilograms (kg) and remains constant whether the object is on Earth, the Moon, or in space.
  • Weight, on the other hand, is the force exerted by gravity on an object and can vary depending on the gravitational pull at different locations.
  • Mass is a scalar quantity, meaning it only has magnitude, whereas weight is a vector quantity, having both magnitude and direction.

Additional Information

  • Weight is calculated using the formula Weight = Mass × Gravitational Acceleration (W = mg).
  • The gravitational acceleration on Earth is approximately 9.8 m/s2, but this value can differ slightly depending on the location.
  • On the Moon, the gravitational acceleration is about 1/6th of that on Earth, which is why objects weigh less on the Moon.
  • Mass is commonly measured using a balance, which compares an unknown mass to a standard mass.
  • Inertia is a concept related to mass, describing an object's resistance to changes in its state of motion.

Question 78

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) 5 6 5 8 6 4 9 5 2 2 4 4 9 3 0 7 5 7 2 9 9 8 8 1 9 1 3 7 2 5 (Right)

How many such odd digits are there, each of which is immediately preceded by an even digit and also immediately followed by an even digit?

  1. AOption (a)

    1

  2. BOption (b)

    3

  3. COption (c)

    4

  4. DOption (d)

    0

View answer & explanation

Correct answer

Answer: (a)A.

1

Why this answer is correct

Given series:

(Left) 5 6 5 8 6 4 9 5 2 2 4 4 9 3 0 7 5 7 2 9 9 8 8 1 9 1 3 7 2 5 (Right)

According to the question such odd digit which are immediately preceded by an even digit and also immediately followed by an even digit:

Required condition: Even - odd - Even

(Left) 5 6 5 8 6 4 9 5 2 2 4 4 9 3 0 7 5 7 2 9 9 8 8 1 9 1 3 7 2 5 (Right)

Thus, there are one such odd digit which are immediately preceded by an even digit and also immediately followed by an even digit.

Hence, "Option 1" is the correct answer.

Question 79

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)

    CJF

  2. BOption (b)

    ELH

  3. COption (c)

    IPL

  4. DOption (d)

    LSP

View answer & explanation

Correct answer

Answer: (d)D.

LSP

Why this answer is correct

Logic follows here is that the first letter is increased by 7 and the second letter is decreased by 4.

Option 1) CJF

Option 2) ELH

Option 3) IPL

Option 4) LSP

Does not follow the same logic.

Hence the correct answer is "Option 4"

Question 80

Read the given statements and select the correct option.

Statement I: Only Sarvepalli Radhakrishnan and C Rajagopalachari were the first recipients of the Bharat Ratna.

Statements II: Sachin Tendulkar was awarded the Bharat Ratna in 2014, and he remains the first and only cricketer to have received this honor till 2024

  1. AOption (a)

    Statement I is incorrect, while statement II is correct.

  2. BOption (b)

    Both statement I and statement II are correct.

  3. COption (c)

    Statement I is correct, while statement II is incorrect.

  4. DOption (d)

    Both statement I and statement II are incorrect.

View answer & explanation

Correct answer

Answer: (a)A.

Statement I is incorrect, while statement II is correct.

Why this answer is correct

The correct answer is Option 1.

Key Points

  • Statement I is incorrect: Because the first Bharat Ratna awardees were three persons in 1954 — C. Rajagopalachari, S. Radhakrishnan, and C.V. Raman.
  • Statement II is correct: Sachin Tendulkar was awarded the Bharat Ratna in 2014, and he is the first and only cricketer to receive this honor as of 2024.

Additional Information

  • Bharat Ratna:
  • It is the highest civilian award in India.
  • Established in 1954, it is awarded for exceptional service towards the advancement of Art, Literature and Science, and in recognition of Public Service of the highest order.
  • The award does not carry any monetary grant but a certificate (Sanad) signed by the President and a medallion.
  • Sarvepalli Radhakrishnan:
  • He was an Indian philosopher and statesman who served as the first Vice President of India and the second President of India.
  • He was awarded the Bharat Ratna in 1954 for his contribution to education and philosophy.
  • C. Rajagopalachari:
  • He was an Indian politician, independence activist, lawyer, writer, and statesman.
  • He was the last Governor-General of India and a founder of the Swatantra Party.
  • He was awarded the Bharat Ratna in 1954 for his public service.
  • Sachin Tendulkar:
  • He is a former Indian cricketer and one of the greatest batsmen in the history of cricket.
  • He was awarded the Bharat Ratna in 2014, making him the youngest recipient and the first sportsperson to receive the award.

Question 81

Rani has borrowed an amount of ₹2,00,000 from a bank to start a business. How much simple interest will she pay at a rate of 7% per annum after 2 years?

  1. AOption (a)

    ₹28,000

  2. BOption (b)

    ₹26,000

  3. COption (c)

    ₹28,500

  4. DOption (d)

    ₹24,000

View answer & explanation

Correct answer

Answer: (a)A.

₹28,000

Why this answer is correct

Shortcut Trick

Total Simple Interest percentage = Rate × Time

Total % = 7% × 2 = 14%

Interest = 14% of ₹2,00,000 = 14 × 2000 = ₹28,000

∴ The correct answer is ₹28,000.

Alternate Method

Given:

Principal (P) = ₹2,00,000

Rate (R) = 7% per annum

Time (T) = 2 years

Formula Used:

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

Calculations:

⇒ SI = (2,00,000 × 7 × 2) ÷ 100

⇒ SI = 2,000 × 14

⇒ SI = 28,000

∴ The correct answer is ₹28,000.

Additional Information

Total Amount Formula

The total amount (A) to be paid after the time period is calculated as Amount = Principal + Simple Interest.

Constant Interest Property

In Simple Interest, the interest amount remains constant every year because it is always calculated on the original Principal.

Rate and Time Units

Ensure that the Rate and Time are in the same time units (e.g., if Rate is per annum, Time must be in years).

Question 82

In the following number-pairs, the second number is obtained by applying certain mathematical operations to the first number. 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.)

153, 17

216, 24

  1. AOption (a)

    171, 18

  2. BOption (b)

    243, 27

  3. COption (c)

    189, 31

  4. DOption (d)

    225, 35

View answer & explanation

Correct answer

Answer: (b)B.

243, 27

Why this answer is correct

Logic:

Formula: First number / 9 = Second number

Given

(153, 17):

153 / 9 = 17

For (216, 24):

216 / 9 = 24

Option 1) (171, 18):

171 / 9 = 19 ≠ 18

Option 2) (243, 27):

243 / 9 = 27

Follow the same logic.

Option 3) (189, 31):

189 / 9 = 21 ≠ 31

Option 4) (225, 35):

225 / 9 = 25 ≠ 35

Conclusion:

Only Option 2 satisfies the given formula.

Therefore, the correct answer is option 2) (243, 27).

Question 83

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 oil is paint.

All paint is brush.

Conclusions:

(I) Some brushes are oil.

(II) No brush is oil.

  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: (a)A.

Only conclusion (I) follows

Why this answer is correct

Statements:

All oil is paint.

All paint is brush.

Possible venn diagram is,

Conclusions:

(I) Some brushes are oil.→ follow(As from venn diagram All oil is paint and all paint is brush then some brushes are oil is possible)

(II) No brush is oil. → Not follow(As from venn diagram All oil is paint and all paint is brush then no brushes is oil is not possible)

Hence the correct answer is "Option 1"

Additional Information

Question 84

The value of a machine depreciates at the rate of 10% per annum. If its present value is ₹1,62,000, then what was the value of the machine 2 years ago?

  1. AOption (a)

    ₹1,90,000

  2. BOption (b)

    ₹2,00,000

  3. COption (c)

    ₹1,86,000

  4. DOption (d)

    ₹2,04,000

View answer & explanation

Correct answer

Answer: (b)B.

₹2,00,000

Why this answer is correct

Shortcut Trick

Rate of depreciation = 10% = 1/10.

Value ratio for 1 year = 10 : 9.

Value ratio for 2 years = 102 : 92 = 100 : 81.

Given, 81 units = ₹1,62,000 → 1 unit = ₹2,000.

Original value (100 units) = 100 × ₹2,000 = ₹2,00,000.

∴ The correct answer is ₹2,00,000.

Alternate Method

Given:

Present Value (Vp) = ₹1,62,000

Rate of depreciation (r) = 10%

Time period (n) = 2 years

Formula Used:

Vp = V0 × (1 − r/100)n

Calculations:

⇒ 1,62,000 = V0 × (1 − 10/100)2

⇒ 1,62,000 = V0 × (90/100)2

⇒ 1,62,000 = V0 × (9/10) × (9/10)

⇒ 1,62,000 = V0 × (81/100)

⇒ V0 = (1,62,000 × 100) ÷ 81

⇒ V0 = 2,000 × 100

⇒ V0 = 2,00,000

∴ The correct answer is ₹2,00,000.

Additional Information

Depreciation Formula

It is similar to Compound Interest but with a negative rate: Amount = Principal × (1 − R/100)T.

Appreciation

If the value increases, the formula becomes: Future Value = Present Value × (1 + R/100)T.

Successive Percentage Change

For two years of depreciation, the effective rate is −a − b + (ab/100). For 10% p.a., effective change = −10 − 10 + 1 = −19%.

Question 85

A, B, C alone can do a piece of work in 9, 12 and 18 days, respectively. They all started the work together, but A left after 3 days. In how many days was the remaining work completed? 

  1. AOption (a)

    52\frac{5}{2}

  2. BOption (b)

    95\frac{9}{5}

  3. COption (c)

    114\frac{11}{4}

  4. DOption (d)

    2

View answer & explanation

Correct answer

Answer: (b)B.

95\frac{9}{5}

Why this answer is correct

Shortcut Trick

Total Work (LCM of 9, 12, 18) = 36 units.

Efficiencies: A = 4, B = 3, C = 2. Combined = 9 units/day.

Work done in 3 days = 9 × 3 = 27 units.

Remaining work = 36 − 27 = 9 units.

Remaining work done by B and C = 9 ÷ (3 + 2) = 9/5 days.

∴ The correct answer is 9/5 days.

Alternate Method

Given: Time taken by A = 9 days, B = 12 days, C = 18 days. A leaves after 3 days.

Formula: Total Work = Efficiency × Time; Remaining Time = Remaining Work ÷ Efficiency of remaining workers.

PersonDaysTotal WorkEfficiency
A93636 ÷ 9 = 4
B1236 ÷ 12 = 3
C1836 ÷ 18 = 2

⇒ Total work done by A, B, and C in 3 days = (4 + 3 + 2) × 3

⇒ Work done = 9 × 3 = 27 units

⇒ Remaining Work = 36 − 27 = 9 units

⇒ Remaining work done by B and C together = 9 ÷ (3 + 2)

⇒ Time taken = 9/5 days

∴ The correct answer is 9/5 days.

Additional Information

Total Work and Efficiency

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

Leaving/Joining Problems

When a person leaves mid-way, subtract the work they completed from the total work and divide the remainder by the efficiency of the remaining workforce.

Work and Wages

Wages are distributed in the ratio of the actual work done by each individual, which is Efficiency × Days worked.

Question 86

In a certain code language, ‘FIRE’ is coded as '3718' and ‘FARE’ is coded as ‘1438'. What is the code for ‘A’ in the given code language?  

  1. AOption (a)

    1

  2. BOption (b)

    3

  3. COption (c)

    4

  4. DOption (d)

    8

View answer & explanation

Correct answer

Answer: (c)C.

4

Why this answer is correct

Logic followed here is

Logic : FRE is common in both the language and 3 1 8 is common in both the code.

So, code for A is 4.

Hence the correct answer is option (3).

Question 87

50 men took a dip in a water tank 40 m long and 20 m broad on a religious day. If the average displacement of water by a man is 4 m3, then the rise in the water level in the tank will be:

  1. AOption (a)

    25 cm

  2. BOption (b)

    20 cm

  3. COption (c)

    50 cm

  4. DOption (d)

    35 cm

View answer & explanation

Correct answer

Answer: (a)A.

25 cm

Why this answer is correct

Shortcut Trick

Total volume of water displaced = Total Men × Average Displacement per man

Total Volume = 50 × 4 = 200 m3

Rise in water level = Total Volume ÷ Area of base = 200 ÷ (40 × 20)

Rise in level = 200 ÷ 800 = 0.25 m = 25 cm

∴ The correct answer is 25 cm.

Alternate Method

Given: Length (L) = 40 m, Breadth (B) = 20 m, Number of men = 50, Average volume per man = 4 m3

Formula Used: Volume of water displaced = Volume of rectangular tank up to rise level = L × B × h

⇒ Total volume of water displaced = 50 × 4 = 200 m3

⇒ Area of the tank base = Length × Breadth = 40 × 20 = 800 m2

⇒ Volume = Area × Rise in level (h)

⇒ 200 = 800 × h

⇒ h = 200 ÷ 800 = 0.25 m

⇒ h in cm = 0.25 × 100 = 25 cm

∴ The correct answer is 25 cm.

Additional Information

Volume Displacement Principle

When an object is submerged in a liquid, it displaces a volume of liquid equal to its own volume (Archimedes Principle). In a fixed container, this results in a rise in level h = Volume ÷ Base Area.

Unit Conversions

Always ensure units are consistent. 1 meter = 100 centimeters; 1 m3 = 1000 liters. Conversion from m to cm requires multiplying by 100.

Cuboid Formulas

Volume = Length × Breadth × Height. Total Surface Area = 2(lb + bh + hl). Lateral Surface Area = 2h(l + b).

Question 88

Different cell organelles such as mitochondria, ribosome, etc., together constitute the basic unit of life called the: 

  1. AOption (a)

    organ 

  2. BOption (b)

    organ system 

  3. COption (c)

    tissue 

  4. DOption (d)

    cell 

View answer & explanation

Correct answer

Answer: (d)D.

cell 

Why this answer is correct

The correct answer is cell.

Key Points

  • A cell is the basic structural and functional unit of life in all living organisms.
  • Organelles such as mitochondria, ribosomes, and others are components within a cell that perform specific functions necessary for the cell's survival and operation.
  • The cell is the smallest unit that can carry out all life processes, including metabolism, growth, and reproduction.
  • Cells can be prokaryotic (without a nucleus, e.g., bacteria) or eukaryotic (with a nucleus, e.g., plant and animal cells).

Additional Information

  • Mitochondria: Known as the powerhouse of the cell, mitochondria generate most of the cell's supply of ATP, used as a source of chemical energy.
  • Ribosomes: These are the sites of protein synthesis, where RNA is translated into protein.
  • Nucleus: The control center of a eukaryotic cell, containing most of the cell's genetic material.
  • Cell Membrane: A biological membrane that separates the interior of all cells from the outside environment, providing protection and structure.
  • Cytoplasm: The material within a cell, excluding the nucleus, which contains organelles and is the site of many metabolic processes.

Question 89

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 villas are buildings.

Some buildings are apartments.

Conclusions:

(I) All buildings are villas.

(II) Some villas are not apartments.

  1. AOption (a)

    Both conclusions I and II follow

  2. BOption (b)

    Neither conclusion I nor II follows 

  3. COption (c)

    Only conclusion I follows

  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

Statements:

All villas are buildings.

Some buildings are apartments.

Possible venn diagram is,

Conclusions:

(I) All buildings are villas.→ Not follow (As all villas are buildings but we can't say that the all buildings are villas.)

(II) Some villas are not apartments. → Not follow (As all villas are buildings, then some villas are not apartments is not possible.)

Hence the correct answer is "Option 2"

Additional Information

Question 90

Who among the following was appointed Indian men's cricket team's full time T20 international captain in July 2024?

  1. AOption (a)

    Ravindra Jadeja

  2. BOption (b)

    Shubman Gill

  3. COption (c)

    Suryakumar Yadav

  4. DOption (d)

    Hardik Pandya

View answer & explanation

Correct answer

Answer: (c)C.

Suryakumar Yadav

Why this answer is correct

The correct answer is Suryakumar Yadav.

Key Points

  • Suryakumar Yadav was appointed as the full-time captain of the Indian men's T20 international team in July 2024.
  • Known for his aggressive batting style, Suryakumar has been a consistent performer in the T20 format.
  • His appointment comes after a series of impressive performances both in domestic cricket and international T20 matches.
  • He succeeded Hardik Pandya, who had been serving as the interim captain for the team.
  • Suryakumar Yadav's leadership is expected to bring a fresh and dynamic approach to the Indian T20 squad.

Additional Information

  • Career Overview:
  • Suryakumar Yadav, also known as SKY, made his debut for the Indian T20 team in March 2021 against England.
  • He is known for his 360-degree playing style, often compared to AB de Villiers.
  • Before his international debut, he was a prominent player in the Indian Premier League (IPL), representing Mumbai Indians.
  • Achievements:
  • He has scored multiple half-centuries and a few centuries in T20 internationals, showcasing his ability to play under pressure.
  • In IPL, he has been one of the top run-scorers for his team, contributing significantly to their victories.
  • Leadership Qualities:
  • His calm demeanor on the field and ability to make strategic decisions have been appreciated by many cricket experts.
  • He has previously captained his state team, Mumbai, in domestic cricket, gaining valuable leadership experience.
  • Impact on Team Dynamics:
  • As a captain, he is expected to foster a positive and aggressive mindset within the team.
  • His rapport with young players and senior members alike will be crucial in building a cohesive unit.

Question 91

Which of the following metals reacts with cold water?

  1. AOption (a)

    Aluminium

  2. BOption (b)

    Zinc

  3. COption (c)

    Iron

  4. DOption (d)

    Sodium

View answer & explanation

Correct answer

Answer: (d)D.

Sodium

Why this answer is correct

The correct answer is Sodium.

Key Points

  • Sodium reacts vigorously with cold water to produce sodium hydroxide (NaOH) and hydrogen gas (H2).
  • The reaction is highly exothermic, meaning it releases a significant amount of heat.
  • Because of its vigorous reaction with water, sodium is stored in kerosene or mineral oil to prevent it from coming into contact with moisture.
  • In the reactivity series of metals, sodium is placed higher up, indicating its high reactivity.

Additional Information

  • Reactivity Series: This is a series of metals arranged in order of decreasing reactivity. The most reactive metals are at the top, and the least reactive are at the bottom.
  • Exothermic Reaction: A chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction.
  • Sodium Hydroxide (NaOH): Also known as caustic soda or lye, it is a highly caustic metallic base and alkali salt used in many industrial processes.
  • Hydrogen Gas (H2): The lightest and most abundant chemical substance in the universe, hydrogen gas is highly flammable and is used in various industrial applications.
  • Storage of Sodium: Due to its high reactivity with water and air, sodium is stored under oil to prevent accidental reactions.

Question 92

Using the empirical relation between the mean, median and mode, find the value of the mode if the median is 30 and mean is 25.

  1. AOption (a)

    330

  2. BOption (b)

    50

  3. COption (c)

    60

  4. DOption (d)

    40

View answer & explanation

Correct answer

Answer: (d)D.

40

Why this answer is correct

Shortcut Trick Empirical formula: Mode = 3 × Median − 2 × Mean Substitute values: Mode = 3 × 30 − 2 × 25 Calculation: 90 − 50 = 40 ∴ The correct answer is 40. Alternate Method Given: Median = 30 Mean = 25 Formula Used: The empirical relationship for a moderately skewed distribution is: Mode = 3(Median) − 2(Mean) Calculations: ⇒ Mode = (3 × 30) − (2 × 25) ⇒ Mode = 90 − 50 ⇒ Mode = 40 ∴ The correct answer is 40. Additional Information Symmetrical Distribution In a perfectly symmetrical distribution, the Mean, Median, and Mode are all equal (Mean = Median = Mode). Skewed Distribution For positively skewed data, Mean > Median > Mode. For negatively skewed data, Mean < Median < Mode. Alternative Formula Form The relation can also be written as: (Mean − Mode) = 3(Mean − Median).

Question 93

What was India’s rank out of 127 countries in the 2024 Global Hunger Index released in October 2024?

  1. AOption (a)

    97

  2. BOption (b)

    111

  3. COption (c)

    105

  4. DOption (d)

    99

View answer & explanation

Correct answer

Answer: (c)C.

105

Why this answer is correct

The correct answer is 105.

Key Points

  • India ranked 105th out of 127 countries in the 2024 Global Hunger Index (GHI), released in October 2024.
  • The GHI is an annual report jointly published by Concern Worldwide and Welthungerhilfe.
  • The index measures and tracks hunger globally using four indicators: undernourishment, child wasting, child stunting, and child mortality.
  • India's ranking indicates a serious level of hunger, reflecting the country's ongoing challenges in addressing malnutrition and food insecurity.
  • India's position in the GHI has seen fluctuation over the years, underscoring the need for sustained efforts to combat hunger and malnutrition.

Additional Information

  • Global Hunger Index (GHI)
  • The GHI is a tool designed to comprehensively measure and track hunger at global, regional, and national levels.
  • Each country's GHI score is calculated based on a formula that combines four indicators: undernourishment, child wasting (low weight for height), child stunting (low height for age), and child mortality.
  • The index ranks countries on a 100-point scale, with 0 being the best score (no hunger) and 100 being the worst.
  • Scores between 20 and 34.9 are classified as "serious," 35 to 49.9 as "alarming," and 50 or more as "extremely alarming."
  • Undernourishment
  • Undernourishment refers to the proportion of the population whose caloric intake is insufficient to meet the minimum dietary energy requirements.
  • This indicator reflects the overall food security status of a population.
  • Child Wasting and Stunting
  • Wasting is a measure of acute malnutrition and indicates a recent and severe process of weight loss, usually as a result of starvation or disease.
  • Stunting is a measure of chronic malnutrition and reflects failure to receive adequate nutrition over a long period, leading to impaired growth and development in children.
  • Child Mortality
  • This indicator measures the mortality rate of children under the age of five, reflecting the fatal synergy between inadequate nutrition and unhealthy environments.
  • High child mortality rates are indicative of broader health and nutrition deficits within a country.

Question 94

Gas to liquid and liquid to solid conversion is: 

  1. AOption (a)

    solidification and condensation respectively 

  2. BOption (b)

    fusion and vaporisation respectively 

  3. COption (c)

    condensation and solidification respectively 

  4. DOption (d)

    sublimation and fusion respectively 

View answer & explanation

Correct answer

Answer: (c)C.

condensation and solidification respectively 

Why this answer is correct

The correct answer is condensation and solidification respectively.

Key Points

  • Condensation: The process of gas transforming into a liquid state.
  • Solidification: The process of liquid transforming into a solid state.
  • Condensation usually occurs when gas cools down and loses energy.
  • Solidification occurs when a liquid cools and its particles lose kinetic energy, forming a solid structure.
  • Both processes are part of the phase transitions governed by temperature and pressure conditions.

Additional Information

  • Phase Transition: The transformation from one state of matter (solid, liquid, gas) to another.
  • Melting: The process where a solid turns into a liquid.
  • Freezing: Another term for solidification, where a liquid turns into a solid.
  • Vaporization: The process where a liquid turns into a gas, including boiling and evaporation.
  • Sublimation: The process where a solid directly transitions into a gas without becoming a liquid first.

Question 95

The cost of 2 tables and 3 chairs is ₹540, while that of 2 tables and I chair is ₹470. What is the cost of 35 chairs?

  1. AOption (a)

    ₹1205

  2. BOption (b)

    ₹1245

  3. COption (c)

    ₹1225

  4. DOption (d)

    ₹1185

View answer & explanation

Correct answer

Answer: (c)C.

₹1225

Why this answer is correct

Shortcut Trick

Difference in quantity = (2 tables + 3 chairs) − (2 tables + 1 chair) = 2 chairs.

Difference in cost = ₹540 − ₹470 = ₹70.

Cost of 2 chairs = ₹70 ⇒ Cost of 1 chair = ₹35.

Cost of 35 chairs = 35 × 35 = ₹1225.

∴ The correct answer is ₹1225.

Alternate Method

Given:

Cost of 2 Tables + 3 Chairs = ₹540 --- (i)

Cost of 2 Tables + 1 Chair = ₹470 --- (ii)

Calculations:

Subtracting equation (ii) from equation (i):

⇒ (2T + 3C) − (2T + 1C) = 540 − 470

⇒ 2C = 70

⇒ C = 70 ÷ 2 = ₹35

⇒ Cost of 35 chairs = 35 × C

⇒ Cost of 35 chairs = 35 × 35 = ₹1225

∴ The correct answer is ₹1225.

Additional Information

Linear Equations in Two Variables

These problems follow the form ax + by = c. When one variable's coefficient is the same in both equations, subtraction eliminates it directly.

Unitary Method

First find the value of a single unit (1 chair) and then multiply by the required quantity (35 chairs) to find the total cost.

Squares Shortcut

For numbers ending in 5, the square is calculated as: (n × (n+1)) followed by 25. For 352: (3 × 4) = 12, so 1225.

Question 96

Which of the following statements is/are correct?

A) Zinc and lead are more reactive elements than copper.

B) Zinc and lead are less reactive elements than copper.

C) An iron nail become yellow in colour when it is dipped in the copper sulphate solutions.

  1. AOption (a)

    Only C

  2. BOption (b)

    Only A and C

  3. COption (c)

    Only A and B

  4. DOption (d)

    Only A

View answer & explanation

Correct answer

Answer: (d)D.

Only A

Why this answer is correct

The correct answer is Option 4.

Key Points

  • Reactivity Series: Zinc is more reactive than copper, and lead is also more reactive than copper. This follows the order of reactivity in the metal reactivity series.
  • Zinc Reactivity: Zinc can displace copper from its compounds due to its higher reactivity.
  • Lead Reactivity: Lead, although less reactive than zinc, is still more reactive than copper.
  • Iron and Copper Sulphate Reaction: An iron nail dipped in copper sulphate solution will turn brownish-red due to the deposition of copper, not yellow.

Additional Information

  • Metal Reactivity Series: This series ranks metals from highest to lowest reactivity. Elements like potassium and sodium are at the top, while gold and platinum are at the bottom.
  • Displacement Reactions: More reactive metals can displace less reactive metals from their compounds in aqueous solutions.
  • Copper Sulphate Solution: It is a blue solution commonly used in school experiments to demonstrate displacement reactions.
  • Iron and Copper Reaction: When iron reacts with copper sulphate, iron displaces copper, forming iron sulphate and copper metal, which deposits on the iron surface.
  • Color Changes in Reactions: The color change in chemical reactions involving transition metals can often indicate the formation of different compounds or the deposition of metals.

Question 97

Carbon has the unique ability to form bonds with other atoms of carbon, giving rise to large molecules. This property is called _____.

  1. AOption (a)

    Cyclisation

  2. BOption (b)

    Polymerisation

  3. COption (c)

    Metallic bonding

  4. DOption (d)

    Catenation

View answer & explanation

Correct answer

Answer: (d)D.

Catenation

Why this answer is correct

The correct answer is Catenation.

Key Points

  • Catenation is the ability of an element to form bonds with other atoms of the same element, leading to the formation of chains or rings.
  • Carbon exhibits the highest degree of catenation due to its tetravalency, which allows it to form four covalent bonds simultaneously.
  • Due to catenation, carbon can form a wide variety of compounds, including long chains, branched chains, and complex ring structures.
  • This property is essential for the formation of complex organic molecules, such as proteins, DNA, and synthetic polymers.

Additional Information

  • Polymerisation:
  • The process by which small molecules, known as monomers, join together to form a large molecule, or polymer.
  • Examples include the formation of polyethylene from ethylene and the creation of proteins from amino acids.
  • Cyclisation:
  • A chemical reaction in which a linear molecule forms a ring structure.
  • Cyclisation is crucial in forming many biological molecules, such as carbohydrates and nucleic acids.
  • Metallic Bonding:
  • A type of chemical bonding that arises from the attraction between metal atoms and the surrounding sea of electrons.
  • It explains many properties of metals, including electrical conductivity and malleability.
  • Allotropes of Carbon:
  • Carbon exhibits various allotropes due to its catenation property, including diamond, graphite, graphene, and fullerenes.
  • Each allotrope has distinct physical properties due to different arrangements of carbon atoms.

Question 98

What is the process by which autotrophs take in substance from outside and in the presence of sunlight, convert them into stored forms of energy?

  1. AOption (a)

    Circulation 

  2. BOption (b)

    Movement 

  3. COption (c)

    Digestion  

  4. DOption (d)

    Photosynthesis

View answer & explanation

Correct answer

Answer: (d)D.

Photosynthesis

Why this answer is correct

The correct answer is Photosynthesis.

Key Points

  • Photosynthesis is the process by which autotrophs like plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy stored in glucose.
  • During photosynthesis, these organisms take in carbon dioxide (CO2) and water (H2O) from their surroundings.
  • The process occurs primarily in the chloroplasts of plant cells, where chlorophyll captures light energy.
  • Oxygen (O2) is released as a by-product of photosynthesis, which is essential for the survival of aerobic organisms.
  • Photosynthesis can be summarized by the chemical equation: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

Additional Information

  • Chlorophyll: A green pigment in plants that absorbs light energy used to carry out photosynthesis.
  • Stomata: Tiny openings on the surfaces of leaves that allow for the exchange of gases (CO2 and O2) with the atmosphere.
  • Thylakoid membranes: Structures within the chloroplasts where the light-dependent reactions of photosynthesis take place.
  • Calvin Cycle: The set of light-independent reactions in photosynthesis that convert carbon dioxide and other compounds into glucose.
  • Energy Storage: The glucose produced in photosynthesis is used by the plant for energy or converted into starch and stored for later use.

Question 99

24-carat gold is called ______.

  1. AOption (a)

    impure gold  

  2. BOption (b)

    pure gold 

  3. COption (c)

    spongy gold 

  4. DOption (d)

    wrought gold 

View answer & explanation

Correct answer

Answer: (b)B.

pure gold 

Why this answer is correct

The correct answer is pure gold.

Key Points

  • Gold purity is measured in karats, with 24 karats being 100% pure gold.
  • Common gold purities include 24K, 22K, 18K, and 14K, where K stands for karats.
  • The highest purity for gold is 24 karats, equating to 99.9% gold.

Additional Information

  • Karat System: The karat system is used to denote the purity of gold, with 24 karats representing pure gold.
  • Alloying: Gold is often alloyed with other metals such as copper or silver to increase its hardness and durability.
  • Gold Standards: Different countries have various standards for gold purity, commonly 22K in India and 18K in Europe.
  • Weight vs. Purity: "Carat" (with a "c") is also a unit of weight used for gemstones, distinct from "karat" (with a "k") for gold purity.
  • Gold Uses: Pure gold (24K) is too soft for everyday wear, hence lower karat gold is used for jewelry to ensure durability.

Question 100

The upward and downward growth of a plant is due to which of the following tropisms? 

  1. AOption (a)

    Geotropism 

  2. BOption (b)

    Phototropism  

  3. COption (c)

    Chemotropism 

  4. DOption (d)

    Hydrotropism 

View answer & explanation

Correct answer

Answer: (a)A.

Geotropism 

Why this answer is correct

The correct answer is Geotropism.

Key Points

  • Geotropism is the growth of plant organs in response to gravity.
  • Roots exhibit positive geotropism, growing downward towards gravitational pull.
  • Shoots exhibit negative geotropism, growing upward away from gravitational pull.
  • This response helps plants to anchor in soil and obtain necessary nutrients and water.
  • The hormone auxin plays a significant role in geotropic responses by redistributing growth in plant cells.

Additional Information

  • Phototropism
  • It is the growth of plant organs in response to light.
  • Shoots usually show positive phototropism by growing towards light sources.
  • Hydrotropism
  • It refers to the growth of plant roots towards moisture or water.
  • This response helps plants maximize water uptake from the soil.
  • Chemotropism
  • It involves growth or movement in response to a chemical stimulus.
  • An example is the growth of pollen tubes towards ovules during fertilization.
  • Plant Hormones
  • Plant hormones like auxins, gibberellins, cytokinins, ethylene, and abscisic acid regulate various growth responses.
  • Auxins are key in phototropic and geotropic responses, influencing cell elongation.

100 questions in the full paper