Two points are located at a distance of 10 m and 15 m from the source of oscillation. The period of oscillation is 0.05 s and the velocity of the wave is 300 m/s. What is the phase difference between the oscillations of two points?

(1) $\frac{\pi }{3}$

(2) $\frac{2\pi }{3}$

(3) $\pi$

(4) $\frac{\pi }{6}$

Two waves are represented by the equations $y_1=a\sin \omega t$ and $y_2=a\cos \omega t.$ The first wave 

(1) Leads the second by $\pi$

(2) Lags the second by $2\pi$

(3) Leads the second by $\frac{\pi }{2}$

(4) Lags the second by $\frac{\pi }{2}$

The distance between two consecutive crests in a wave train produced in a string is 5 cm. If 2 complete waves pass through any point per second, the velocity of the wave is :

1. 10 cm/sec

2. 2.5 cm/sec

3. 5 cm/sec

4. 15 cm/sec

A tuning fork makes 256 vibrations per second in air. When the velocity of sound is 330 m/s, then the wavelength of the tone emitted is :

1. 0.56 m

2. 0.89 m

3. 1.11 m

4. 1.29 m

Sound waves have the following frequencies that are audible to human beings :

1. 5 c/s

2. 27000 c/s

3. 5000 c/s

4. 50,000 c/s

The minimum audible wavelength at room temperature is about

1. 0.2 Å

2. 5 Å

3 5 cm to 2 metre

4. 20 mm

The ratio of the speed of sound in nitrogen gas to that in helium gas, at 300 K is 

1.  $\sqrt{2/7}$

2.  $\sqrt{1/7}$

3.  $\sqrt{3}/5$

4.  $\sqrt{6}/5$

The frequency of a rod is 200 Hz. If the velocity of sound in air is 340 ms^–1, the wavelength of the sound produced is :

1. 1.7 cm

2. 6.8 cm

3. 1.7 m

4. 6.8 m

A stone is dropped into a lake from a tower 500 metre high. The sound of the splash will be heard by the man approximately after 

[Given : Speed of sound = 340 m/s ]

1. 11.5 seconds

2. 21 seconds

3. 10 seconds

4. 14 seconds