SOLVED PAPER 2023 (CDS) (II) (General Studies)

Total Questions: 120

1. A person can see near objects clearly through his eyes but cannot see distant objects clearly. The possible reason(s) for this defect could be:

1. Excessive curvature of the eye lens.
2. The eye-ball has become too small.
3. The focal length of the eye lens is too large.
4. Elongation of the eye-ball.

Select the correct answer using the codes given below.

Correct Answer: (c) 1 and 4
Solution:A person can see near objects clearly through his eyes but cannot see the distance objects clearly. The possible reason for this effect could be the focal length of the eye lens is too large. This disorder of the eye is called myopia.

2. Consider a journey by a car represented by the graph given below in three parts A, B and C.

The speed of the car in these parts is V𝔞, V𝔟 and V𝔠 respectively:

Which one of the following is correct in this case?

Correct Answer: (b) V𝔟 > V𝔞 > V𝔠
Solution:A journey by a car represented by the graph given above in three parts A, B-and C. The speed of the car in these parts is V𝔞 V𝔟 and V𝔠 respectively V𝔟 > V𝔞 > V𝔠 It is because we know that distance is proportional to the speed distance of part B > distance of part A > distance of part C.

3. A concave mirror of radius of curvature 50 cm is used to form an image of an object kept at a distance of 25 cm from the mirror on its principal axis. What will be the position of the image from the mirror?

Correct Answer: (a) At infinity
Solution:Given; Radius of Curvature (R) = -50cm

4. If the Moon is brought closer to the Earth such that its distance from the Earth becomes half of the original distance, then the gravitational force of attraction between the Earth and the Moon would

Correct Answer: (d) increase to four times of its original value.
Solution:

5. Sonic boom is produced when a source of sound travels at a speed

Correct Answer: (a) greater than the speed of sound.
Solution:Sonic boom is produced when a source of sound travels at a speed greater than the speed of sound. This generate enormous amount of sound energy and sounding like an explosion.

6. Which one among the following are the correct symbols for the element gold, till and lead, respectively?

Correct Answer: (c) Au, Sn, Pb
Solution:The correct symbols for the element gold, tin and lead are Au, Sn, Pb.
Gold - Au
Tin - Sn
Lead - Pb

7. How much percentage of carbon dioxide is present in the atmosphere of Venus and Mars?

Correct Answer: (d) 95-97%
Solution:95-97% of carbon dioxide is present in the atmosphere of Venus and Mars which is result of volcanic eruption and shrine effect. Due to which CO₂ gets dispersed in the atmosphere of Venus. Therefore this planet is more hotter and denser than the Earth.

8. Which among the following methods is used to separate the constituents present in a compound?

Correct Answer: (a) Electrochemical method
Solution:Electrochemical method is used to separate the constituents present in a compound. The elements in a compound are chemically combined and require a chemical or an electrochemical method to separate them.

9. During white-washing of walls, slaked lime reacts slowly with carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Which of the following reactions represents this correctly?

Correct Answer: (d) Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + H₂O(1)
Solution:During white-washing of walls, slaked lime reacts slowly with carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + H₂O(1)

10. Which one of the following equations is the balanced chemical equation for the given reaction?

Fe + H₂O → Fe₃ O₄ + H₂

Correct Answer: (c) 3Fe + 4H₂O → Fe₃ O₄ + 4H₂
Solution:Fe + H₂O → Fe₃ O₄ + H₂
Balanced chemical equation for the above reaction.
3Fe + 4H₂O → Fe₃ O₄ + 4H₂