SOLVED PAPER 2022 (CDS) (I) (General Awareness)

Total Questions: 120

21. An object weighs 9 N on the surface of the Earth What would be its weight, when measured on the surface of a planet where the acceleration due to gravity is 9 times that on the surface of the Earth?

Correct Answer: (c) The weight would become 9 times
Solution:It is given that the gravity on the surface of another planet is 9 times that on the surface of Earth. Thus, weight (w)= mass × acceleration due to gravity will become 9 times that on the surface of the Earth.

22. The twinkling of a star is due to

Correct Answer: (b) atmospheric refraction of starlight
Solution:Stars are very far away from us. The light coming from the stars suffers multiple refractions due to continuously varying atmospheric density and hence its refractive index. Hence, stars twinkle due to atmospheric refraction of starlight.

23. A convex lens has a focal length of 15 cm. At what distance should an object be placed in front of the lens to get a real image of the same size of the object ?

Correct Answer: (c) 30 cm
Solution:To get the real image of same
size, an object should be placed at
centre of curvature in front of the lens.
i.e. u = R = 2f
= 2 × 15 = 30 cm (∵ f = 15 cm given)

24. Which one of the following statements about biogas is not correct?

Correct Answer: (b) It is a non-renewable source of energy.
Solution:All the statements given are correct, except for the statement given in option (b). It can be corrected as biogas is a renewable source of energy.

25. Which of the following mineral acids is found in human stomach ?

Correct Answer: (a) Hydrochloric acid
Solution:Stomach is a thick walled, J-shaped bag. The inner lining of stomach secretes hydrochloric acid and other digestive juices. The hydrochloric acid (HCI) kills several bacteria which enter the stomach along with food and also help in the activation of protein digestion enzyme.

26. Which one of the following living organisms gives litmus?

Correct Answer: (c) Lichen
Solution:Litmus is extracted from Lichen. Roccella molagnei and Dendrographa leucophaea are the main sources. The litmus paper is used as a pH indicator to test the acidity and basidity of a solution.

27. Which one of the following is the main reason of acid rains?

Correct Answer: (a) Dissolution of sulphur and nitrogen oxides in rain.
Solution:The main cause of acid rain is the dissolutions of sulphur and nitrogen oxide in rain. These oxides emitted by vehicles and industries, rise high in atmosphere and react with rain water, This reaction forms H₂SO₄ and HNO₃ which lowers the pH level of rain water. Acid rain can cause harmful effects like decolouration of monuments (e.g. Taj Mahal) and buildings, loss of soil futility, skin allergies in humans etc.

28. Mutation in a virus is caused due to a change in its

Correct Answer: (b) genetic material
Solution:Mutation in a virus is caused due to a change in its genetic material. Every organism has its own genetic material which contains information about the organism's multiplication, development behaviour etc. In virus the genetic material is RNA. During the mutation process in viruses, genetic material is subjected to molecular processes in order to obtain functional protein products. In one such process the genetic materials attempt to replicate themselves. They make some mistakes while copying which cause change in resulting protein leading to mutation.

29. Yeast, which is used to make bread, belongs to the group

Correct Answer: (b) Fungi
Solution:Yeast, scientifically named as Saccharomyces cerevisiae is a saprophytic fungus. These are unicellular organisms with variable sizes. Yeasts find their usage in the food and beverage industry for preparing ethanol via fermentation.

30. Hyphae are

Correct Answer: (b) thin threads formed by many fungi.
Solution:Fungal body consists of long, extremely fine transparent threads called hyphae. These hyphae when many in number, get twined around one another to form mycelium. Hyphae are involved in asexual reproduction.