set 16 MCQ Questions & Answers Detailed Explanation

Question : 1

Human ears can sense sound waves travelling in air having wavelength of

a) 1m

b) 10^–3 m

c) 10^–2 m

d) 10² m

Question : 2

A person cannot see objects clearly which are nearer than 75 cm from his eyes, the disease he is suffering from is

a) hypermetropia

b) astigmatism

c) myopia

d) presbyopia

Question : 3

A star is emitting yellow light. If it is accelerated towards earth then to an observer on earth, it will appear

a) gradually changing to red

b) shinning yellow

c) gradually changing to violet

d) unchanged

Question : 4

Opening the door of refrigerator kept in the room

a) You can cool the room to the temperature of refrigerator

b) You are warm the room a little

c) You can cool the room to some degree

d) You can neither cool nor warm the room

Question : 5

In driving a car which type of mirror would you like to use for observing traffic at your back?

a) Convex mirror

b) Spherical mirror

c) Concave mirror

d) Plain mirror

Question : 6

The reflection of sound is called echo. Which of the following conditions is/ are necessary for the formation of echo?

1. The minimum distance between the source of sound and the reflecting body should be 17 m.
2. The wavelength of sound should be less than the height of the reflecting body.

a) 1 and 2 both

b) 1 only

c) 2 only

d) None