set 7 MCQ Questions & Answers Detailed Explanation

Question : 1

Two astronauts cannot hear each other on the Moon’s surface, because

a) No atmosphere on the Moon

b) They wear special space suits on the Moon

c) Their ears have stopped working on the Moon

d) The sound travels much more slowly on Moon

Question : 2

The velocity of sound in any gas depends upon

a) intensity of sound waves only

b) wavelength of sound only

c) density and elasticity of gas

d) amplitude and frequency of sound

Question : 3

Consider the following statements.

1. Fibre optics is based on the principle of total internal reflection.
2. In an optical fibre communication system, power consumption is extremely low.
3. Optical fibre communications are free from radio frequency interference.
4. In India, Reliance Group of Industries is engaged in the manufacture of the optical fibre.

a) 1, 3 and 4

b) 1, 2 and 4

c) 1, 2 and 3

d) 2, 3 and 4

Question : 4

Two pulses travel in mutually opposite directions in a string with a speed of 2.5 cm/s as shown in the figure. Initially the pulses are 10 cm apart. What will be the state of the string after two seconds

a)

b)

c)

d)

Question : 5

Expansion during heating

a) Increases the weight of the material

b) Decreases the density of the material

c) Occurs only in solid

d) Occurs at the same rate for all liquids and solids

Question : 6

The concept of expanding universe is based on

a) Zeeman effect

b) Stark effect

c) Doppler effect

d) Raman effect