set 7 MCQ Questions & Answers Detailed Explanation

Question : 1

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 : 2

The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason ?

a) The density of water is maximum at 4°C.

b) Since the surface of the lake is at the same temperature as the air, no heat is lost.

c) Ice is a bad conductor of heat.

d) None

Question : 3

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 : 4

The concept of expanding universe is based on

a) Zeeman effect

b) Stark effect

c) Doppler effect

d) Raman effect

Question : 5

Match List I with List II and select the correct answer using the codes given below the lists.

a) A – 4, B – 1, C – 2, D – 3

b) A – 2, B – 1, C – 4, D – 3

c) A – 2, B – 3, C – 4, D – 1

d) A – 4, B – 3, C – 2, D – 1

Question : 6

Reading glasses are made from which type of lenses?

a) Plain

b) Convex

c) Concave

d) None of these