The echo of a gunshot is heard 8 sec. after the gun is fired. How far from him is the surface that reflects the sound? (velocity of sound in air = 350 m/s) :

1. 1400 m

2. 2800 m

3. 700 m

4. 350 m

A man sets his watch by the sound of a siren placed at a distance 1 km away. If the velocity of sound is 330 m/s

1. His watch is set 3 sec. faster

2. His watch is set 3 sec. slower

3. His watch is set correctly

4. None of the above

The velocity of sound in air is:

The frequency of a sound wave is n and its velocity is v. If the frequency is increased to 4n, the velocity of the wave will be 

(1) v

(2) 2v

(3) 4v

(4) v/4

The speed of a wave in a certain medium is 960 m/s. If 3600 waves pass over a certain point of the medium in 1 minute, the wavelength is :

(1) 2 metres

(2) 4 metres

(3) 8 metres

(4) 16 metres

Sound velocity is maximum in :

(1) H₂

(2) N₂

(3) He

(4) O₂

The minimum distance of reflector surface from the source for listening the echo of sound is :

(1) 28 m

(2) 18 m

(3) 19 m

(4) 16.5 m

The type of waves that can be propagated through solid is :

(1) Transverse

(2) Longitudinal

(3) Both (1) and (2)

(4) None of these

Velocity of sound in air

I. Increases with temperature

II. Decreases with temperature

III. Increase with pressure

IV. Is independent of pressure

V. Is independent of temperature

Choose the correct answer.

(1) Only I and II are true

(2) Only I and III are true

(3) Only II and III are true

(4) Only I and IV are true