Search Previous Year Questions

Given sign interchanges:

The given equation is:

5 ÷ 2 + 16 × 4 − 4 = ?

After interchanging the signs as per the instructions, the equation becomes:

= 5 × 2 − 16 ÷ 4 + 4

= 5 × 2 - 4 + 4

= 10 - 4 + 4

= 10

Therefore, the value that will come in place of the question mark is 10.

Hence, the correct answer is "Option 2".

Given:

Let us first decode the given symbols and then draw a family tree.

On checking: G + H div I − J × K

1. G + H - 'G + H' means 'G is the mother of H'.

2. H div I - 'H div I' means 'H is the daughter of I'.

3. I − J - 'I − J' means 'I is the brother of J'.

4. J × K - 'J × K' means 'J is the sister of K'.

Since G is the mother of H and I is the father of H, G is the wife of I. As I is the brother of K, G is the Brother's wife of K.

Hence, the correct answer is 'Option 1'.

Logic followed here is.

Logic: The code for a specific letter is determined by identifying the common letter across different words and the corresponding common digit in their codes.

For

CRAB is coded as 8642

BENT is coded as 1358

By the method of comparison, since 'B' is the only common letter and '8' is the only common digit, the code for 'B' must be 8.

Hence, the correct answer is "Option 1".

The logic followed here is:

Total number of people in the row = 45

Position of Pari from the right end = 14^th

Bittu sits 20^th to the left of Pari.

Position of Bittu from the right end = Position of Pari from the right end + 20

= 14 + 20

= 34^th

To find Bittu’s position from the left end, we use the formula:

Position from the left = (Total number of people − Position from the right) + 1

= (45 − 34) + 1

= 11 + 1

= 12^th

Hence, the correct answer is 'Option 2'.

Logic followed here is the comparison of the common letters and their corresponding digits in the given coded words.

For the given words:

MIND is coded as '7542'

DOPE is coded as '1436'

Therefore, the code for 'D' is 4.

Hence, the correct answer is "Option 4".

The correct answer is Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl.

Key Points

• A double displacement reaction is a type of chemical process where two compounds react, and the positive ions (cations) and the negative ions (anions) of the two reactants switch places to form two new compounds.
• In the reaction Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl, the Sodium ions (Na⁺) from sodium sulfate pair with the Chloride ions (Cl⁻) from barium chloride.
• Simultaneously, the Barium ions (Ba²⁺) pair with the Sulfate ions (SO₄²⁻) to form Barium sulfate.
• This specific reaction is also classified as a precipitation reaction because Barium sulfate is an insoluble white solid that settles out of the solution.
• The general representation for such reactions is AB + CD → AD + CB, where A and C are cations, and B and D are anions.

 Additional Information

• Decomposition Reaction:
• Seen in CaCO₃ → CaO + CO₂, where a single reactant breaks down into two or more simpler products upon heating (thermal decomposition).
• Combination Reaction:
• Represented by 2H₂ + O₂ → 2H₂O, where two or more substances combine to form a single new product.
• Single Displacement Reaction:
• Exemplified by Fe + CuSO₄ → FeSO₄ + Cu, where a more reactive metal (Iron) displaces a less reactive metal (Copper) from its salt solution.
• Reactivity Series: This governs single displacement reactions, ensuring that only a higher-ranking element can displace a lower-ranking one.

The correct answer is Image is formed at 1.5 m behind the mirror.

Key Points

• For a Convex Mirror, the Radius of Curvature (R) is always taken as positive. Given R = +4.00 m, the Focal Length (f) is calculated using the relation f = R/2, which gives f = +2.00 m.
• According to the New Cartesian Sign Convention, the Object Distance (u) is always negative because the object is placed in front of the mirror. Here, u = −6.00 m.
• The Mirror Formula is expressed as 1/f = 1/v + 1/u, where v represents the Image Distance.
• Rearranging the formula to solve for the image distance: 1/v = 1/f − 1/u. Substituting the known values: 1/v = 1/2.00 − 1/(−6.00).
• This simplifies to 1/v = 1/2.00 + 1/6.00. Taking the Least Common Multiple (LCM) of 2 and 6, we get 1/v = (3 + 1) / 6.00 = 4 / 6.00.
• Calculating the reciprocal, v = 6.00 / 4 = +1.5 m. The positive sign indicates that the image is formed on the other side of the mirror.

 Additional Information

• Nature of Image:
• In a Convex Mirror, the image formed for a real object is always Virtual and Erect.
• The image is located between the Pole (P) and the Principal Focus (F) behind the mirror.
• The Magnification (m) is given by m = −v/u. In this case, m = −1.5 / (−6.0) = +0.25. Since 0 < m < 1, the image is diminished (smaller than the object).
• Practical Application:
• Rear-view Mirrors: Convex mirrors are used in vehicles because they provide a wider field of view compared to plane mirrors, allowing drivers to see traffic over a large area behind them.
• The images are always upright, which is essential for safe driving observations.

The correct answer is Xylem.

Key Points

• Xylem is classified as a complex permanent tissue because it consists of several types of cells—tracheids, vessels, xylem parenchyma, and xylem fibres—that function together as a single unit to transport fluids.
• Its primary physiological role is the unidirectional transport of water and dissolved minerals from the soil, absorbed by roots, to the leaves and other aerial parts of the plant.
• The conducting elements, namely tracheids and vessels, are dead cells at maturity characterized by thickened lignified walls, which provide significant mechanical strength to the plant body.
• The movement of water through the xylem is facilitated by physical forces such as transpiration pull and root pressure, forming a continuous water column throughout the plant.
• Xylem parenchyma is the only living component of the xylem tissue, primarily involved in the storage of food and the lateral conduction of water.

 Additional Information

• Phloem:
• It is a complex permanent tissue responsible for the bidirectional translocation of organic nutrients (food), primarily sucrose, from leaves to storage organs.
• It comprises sieve tubes, companion cells, phloem parenchyma, and phloem fibres.
• Simple Permanent Tissues:
• Parenchyma: These are living cells with thin cellulosic walls; they are specialized for photosynthesis, storage, and secretion.
• Collenchyma: Composed of living cells with unevenly thickened corners due to cellulose and pectin deposits, providing flexibility and mechanical support to young plant parts like petioles.

The correct answer is 4 g of hydrogen and 32 g of oxygen.

Key Points

• The calculation is based on the Law of Definite Proportions (also known as Proust's Law), which states that a chemical compound always contains its component elements in a fixed ratio by mass, regardless of its source.
• Given that 9 g of water contains 1 g of hydrogen and 8 g of oxygen, the mass ratio of Hydrogen to Oxygen in water is established as 1:8.
• To determine the components in 36 g of water, we calculate the proportionality constant by dividing the target mass by the reference mass: 36 g ÷ 9 g = 4.
• By applying this factor of 4 to the original components, the mass of hydrogen required is 1 g × 4 = 4 g.
• Similarly, the mass of oxygen required is 8 g × 4 = 32 g.
• The sum of the individual masses (4 g + 32 g) equals the total mass of 36 g, satisfying the Law of Conservation of Mass.

 Additional Information

• Law of Constant Proportions:
• This fundamental law of stoichiometry was formulated by the French chemist Joseph Proust in 1799.
• It confirms that a pure chemical substance like H₂O will always have the same elements in the same mass percentage.
• Composition of Water:
• Water is composed of two hydrogen atoms and one oxygen atom.
• Considering the approximate atomic masses (H ≈ 1 u, O ≈ 16 u), the molecular mass of water is 18 u.
• The mass ratio is (2 × 1) : 16, which simplifies to 1:8, perfectly aligning with the experimental data provided in the question.

The correct answer is binary fission.

Key Points

• Binary fission is a specific type of asexual reproduction where a single parent organism divides into two equal and identical daughter cells.
• The process initiates with the replication of DNA, ensuring each new cell receives a copy of the genetic blueprint.
• This is followed by karyokinesis, the division of the nucleus, and subsequent cytokinesis, the division of the cytoplasm and organelles.
• It is the most common mode of reproduction in prokaryotic organisms such as Bacteria and Archaea, allowing for exponential population growth in favorable environments.
• In unicellular eukaryotes like Amoeba, the division can happen in any plane, whereas in Leishmania, which has a flagellum at one end, division occurs in a longitudinal plane.
• Because the daughter cells are genetically identical to the parent, they are considered clones.

 Additional Information

• Budding:
• A process where a new individual develops as an outgrowth or bud from the parent body due to repeated cell division at a specific site.
• Commonly observed in organisms like Yeast (unicellular) and Hydra (multicellular).
• Multiple Fission:
• A method where a single parent cell divides into many daughter cells simultaneously.
• The malarial parasite Plasmodium uses this method to replicate rapidly within a host cell.
• Fragmentation:
• Occurs when a multicellular organism breaks into multiple pieces or fragments upon reaching maturity, and each piece regenerates into a new organism.
• This is a characteristic reproductive method for Spirogyra and certain planarians.