If the density of oxygen is 16 times that of hydrogen, what will be the ratio of their corresponding velocities of sound waves :

1. 1 : 4

2. 4 : 1

3. 16 : 1

4. 1 : 16

At which temperature the speed of sound in hydrogen will be the same as that of the speed of sound in oxygen at 100°C :

1. – 148°C

2. – 212.5°C

3. – 317.5°C

4. – 249.7°C

The phase difference between two points separated by 1m in a wave of frequency 120 Hz is 90°. The wave velocity is :

1. 180 m/s

2. 240 m/s

3. 480 m/s

4. 720 m/s

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