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

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 type of waves that can be propagated through solid is :

(1) Transverse

(2) Longitudinal

(3) Both (1) and (2)

(4) None of these

A wave of the frequency of 500 Hz has a velocity of 360 m/sec. The distance between two nearest points 60° out of phase is :

(1) 0.6 cm

(2) 12 cm

(3) 60 cm

(4) 120 cm

A wavelength 0.60 cm is produced in air and it travels at a speed of 300 ms^–1. It will be an 

(1) Audible wave

(2) Infrasonic wave

(3) Ultrasonic wave

(4) None of the above

An observer standing near the seashore observes 54 waves per minute. If the wavelength of the water wave is 10m then the velocity of a water wave is :

(1) 540 ms^-1

(2) 5.4 ms^-1

(3) 0.184 ms^-1

(4) 9 ms^-1

The equation of a wave is $y=2\sin \pi (0.5x-200t)$, where x and y are expressed in cm and t in sec. The wave velocity is :

1. 100 cm/sec

2. 200 cm/sec

3. 300 cm/sec

4. 400 cm/sec

Two waves are given by $y_1=a\sin (\omega t-kx)$ and $y_2=a\cos (\omega t-kx)$. The phase difference between the two waves is :

(1) $\frac{\pi }{4}$

(2) π

(3) $\frac{\pi }{8}$

(4) $\frac{\pi }{2}$