SOLVED PAPER 2024 (CDS) (II) (General Knowledge)

Total Questions: 120

21. X-rays can be used to

1. inspect welded joints between two metal parts of a machine
2. study structure of crystals
Select the answer using the codes given below:

Correct Answer: (c) Both 1 and 2
Solution:Both statements (1) and (2) are correct. X-ray is suitable method for weld inspections because technicians do not have to alter or destroy the object to thoroughly analyze it. X-ray is also a flexible method that can be used on almost any material. X-rays require access to two opposite sides of the weld.

X-rays are used to study crystal structures because they have wavelengths that are similar to the size of atoms and are able to penetrate matter easily.

22. Which one of the following heat transfers is an example of convection?

Correct Answer: (b) Boiling water in a pot on a gas stove.
Solution:Convection is the transfer of heat from high energy particles to low energy particles by bulk or macroscopic movement of fluid particles over a solid surface. e.g., Boiling water. In this the heat passes from the burner into the pot, heating the water at the bottom.

The heat of the Sun and the cooking action of a microwave are both forms of radiation.

23. The phenomenon of rainbow formation by water droplets involves

Correct Answer: (d) both refraction and internal reflection of sunlight
Solution:The formation of rainbow involves all three phenomenon: Refraction, dispersion and total internal reflection. The sunlight shines on a water droplet. As the light passes into the raindrop the light bends or refracts. Due to slow down of light, white light gets dispersed into seven colours.

24. Ozone hole is a region over

Correct Answer: (c) the Arctic caused mainly by CFC gases
Solution:The ozone hole is a region of depleted ozone in the stratosphere over the Antarctic. The ozone hole is caused by human activities that release ozone-depleting substances into the atmosphere, such as chlorofluorocarbons (CFCs) and other ozone-depleting substances.

25. Which of the following are the major missions of Indian Space Research Organisation in 2023?

1. Chandrayaan-3
2. Solar Mission Aditya-L1
3. Liquid fuel powered rockets
4. Solar powered rockets
Select the answer using the codes given below.

Correct Answer: (a) 1 and 2
Solution:In the year 2023, seven missions were launched by ISRO, namely SSLV-D2/EOS7, LVM3-

M3/ONEWEB II, PSLV-C55/TLEOS-2, GSLV-F12 NVS-01,

LVM3-M4/Chandrayaan-3, PSLV-C56/DS-SAR and PSLV-C57/Aditya L-1.

ISRO achieved a major milestone with the successful hot testing of liquid rocket engine manufactured through Additive Manufacturing (AM) technology for a duration of 665 s on May 9th, 2024. The engine used is the PS4 engine of PSLV upper stage.

26. Which one of the following is the most appropriate reason for aircraft being equipped with conducting tyres?

Correct Answer: (d) For preventing sparks while they land on the ground.
Solution:On landing of an aircraft, the friction between the tires and the runway can cause static electricity to build up on the aircraft's surface.

This build up of static charge can lead to sparks, which can potentially ignite flammable vapours or fuel. So, an aircraft being equipped with conducting tires because these tires help to dissipate this static charge safely by providing a path for it flow to the ground.

27. Which of the following statements for persons suffering from presbyopia is/are correct?

1. They cannot distinguish colours.
2. It usually develops with ageing.
3. They wear either bifocal lenses consisting of both concave and convex lenses or progressive lenses.
Select the answer using the codes given below.

Correct Answer: (d) 2 and 3
Solution:The statements (2) and (3) are correct. Presbyopia is a common eye condition that develops with age. It occurs when the lens of the eye loses it flexibility and becomes less able to focus on nearby objects. It does not affect colour vision. People with presbyopia often wear bifocal or progressive lenses to correct their vision.

28. A sound wave having frequency of 300 Hz is travelling in an unknown medium. Its wavelength is not known. It travels a distance equal to 150 times its wavelength in time t. The value of t is

Correct Answer: (a) 0.5 s
Solution:Let the wavelength of the wave is λ.
Given, the distance travelled by the wave is d = 150λ
The time travel of wave is,

29. Mission Shakti (DRDO) of India is related to which one among the following?

Correct Answer: (d) Use of rocket to destroy an orbiting satellite.
Solution:Mission Shakti is a space mission conducted by the Defence Research and Development Organisation (DRDO) of India that involved successfully neutralising a satellite in space with an anti- satellite (ASAT) missile.

DRDO successfully neutralised a satellite in space with its anti-satellite (ASAT) missile on 27th March, 2019, in Mission Shakti. The successful mission demonstrated DRDO's technical prowess and ability to defend country's assets in space, the 4th dimension of warfare.

30. In Sun-Earth system, the Sun, the Earth and the Lagrange point L₄ form

Correct Answer: (b) an equilateral triangle
Solution:The L₄ point is one of the five lagrange points in the Sun-Earth system where the gravitational forces of the Sun the Earth, along with centripetal force of an orbiting object, balance to create a stable point. The distances between L₄ and the Sun and between L₄ and the Earth, are equal. So, L₄ forms an equilateral triangle with the Sun and Earth.