# CSAT Prelims Physics - General Knowledge Questions and Answers for UPSC Exam | Page-6

Questions
51 The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason ?
A Ice is bad conductor of heat.
B The density of water is maximum at 40C.
C Since the surface of the lake is at the same temperature as the air, no heat is lost.
D None of the statements (A), (B) and (C) given is correct.

52 The clouds float in the atmosphere because of their low:
A pressure
B density
C velocity
D temperature

53 Consider the following statements: If there were no phenomenon of capillarity
I. it would be difficult to use a kerosene lamp
II. one would not be able to use a straw to consume a soft drink
III. the blotting paper would fail to function
IV. the big trees that we see around would not have grown on the earth

Which of the statements given above are correct ?

A I, II and III only
B I, III and IV
C II and IV
D I, II, III and IV

54 Consider the following phenomena:
I. Size of the sun at dusk.
II. Colour of the sun at dusk.
III. Moon being visible at dawn.
IV. Twinkle of stars in the sky.
V. Polestar being visible in the sky.

Which of the above are optical illusions ?

A I, II and III
B III, IV and V
C I, II and IV
D II, III and V

55 Two wires have their lengths, diameters and resistivity all in the ratio of 1: 2. If the resistance of the thinner wire is 10 ohm, the resistance of the thicker wire is:
A 5 ohm
B 10 ohm
C 20 ohm
D 40 ohm

56 When a mirror is rotated by an angle θ, the reflected ray will rotate by:
A 00
B θ/2
C θ
D

57 Consider the following statements: A 4-wheel vehicle moving in a sharp circular path at high speed will:
I. overturn about its outer wheels
II. overturn about its inner wheels
III. skid outwards
IV. skid inwards

Which of these statements are correct ?

A I and III
B II, and IV
C II and III
D I and IV

58 Consider the following statements:
I. If a person looks at a coin which is in a bucket of water, the coin will appear to be closer than it really is.
II. If a person under water looks at a coin above the water surface, the coin will appear to be at a higher level than it really is.

Which of the above statements is/are correct ?

A I and II
B I only
C II only
D Neither I nor II

59 When light waves pass from air to glass, the variables affected are:
A velocity and frequency
B wavelength and frequency
C wavelength and velocity
D wavelength, frequency and velocity