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# CSAT Prelims Physics - General Knowledge Questions and Answers for UPSC Exam | Page-3

Questions
21 Optical fiber works on the principle of:
A refraction
B scattering
C interference
D total internal reflection

22 Three identical vessels A, B and C are filled water, mercury and kerosene respectively up to an equal height. The three vessels are provided with identical taps at the bottom of the vessels. If the three taps are opened simultaneously, then which vessel is emptied first ?
A Vessel A
B Vessel B
C Vessel C
D All the vessels A, B and C will be emptied simultaneously

23 Which one of the following is the correct sequence of the given substances in the decreasing order of their densities ?
A Steel> Gold> Mercury
B Steel> Mercury> Gold
C Gold> Mercury> Steel
D Gold> Steel> Mercury

24 Consider the following statements: A simple pendulum is set into oscillation. Then:
I. the acceleration is zero when the bob passes through the mean position.
II. in each cycle the bob attains a given velocity twice.
III. both acceleration and velocity of the bob are zero when it reaches its extreme position during the oscillation.
IV. the amplitude of oscillation of the simple pendulum decreases with time.

Which of these statements are correct ?

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

25 A girl is swinging on a swing in sitting position. When the girl stands up, the period of swing will:
A be longer
B be shorter
C depends on the height of the girl
D not change

26 Who among the following anticipated Newton by declaring that all things gravitate to the earth ?
A Brahmagupta
B Buddhagupta
C Varahamihira
D Aryabhatta

27 Which one of the following is a vector quantity ?
A Work
B Energy
C Pressure
D Momentum

28 Consider the following features of newer models of motor cars:
II. Streamlined body
III. Multipoint fuel injection
IV. Catalytic converter with exhaust

Which of these features make the new models of motor cars more fuel efficient ?

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

29 The working principle of a washing machine is:
A dialysis
B diffusion
C centrifugation
D reverse osmosis

30 If the radius of earth were to shrink by one percent, its mass remaining the same, the value of g on the earth’s surface would:
A increase by 0.5%
B increase by 2%
C decrease by 0.5%
D decrease by 2%