When two sound waves are superimposed, beats are produced when they have :

(1) Different amplitudes and phases

(2) Different velocities

(3) Different phases

(4) Different frequencies

A tuning fork A of frequency 200 Hz is sounded with fork B, the number of beats per second is 5. By putting some wax on A, the number of beats increases to 8. The frequency of fork B is :

(1) 200 Hz

(2) 195 Hz

(3) 192 Hz

(4) 205 Hz

Two tuning forks have frequencies 380 and 384 Hz respectively. When they are sounded together, they produce 4 beats. After hearing the maximum sound, how long will it take to hear the minimum sound?

(1) $\frac{1}{2}$sec

(2) $\frac{1}{4}$sec

(3) $\frac{1}{8}$sec

(4) $\frac{1}{16}$sec

A couple of tuning forks produces 2 beats in the time interval of 0.4 seconds. So the beat frequency is :

(1) 8 Hz

(2) 5 Hz

(3) 2 Hz

(4) 10 Hz

It is possible to hear beats from the two vibrating sources of frequency :

(1) 100 Hz and 150 Hz

(2) 20 Hz and 25 Hz

(3) 400 Hz and 500 Hz

(4) 1000 Hz and 1500 Hz

Two sound waves of wavelengths 5m and 6m formed 30 beats in 3 seconds. The velocity of sound is :

(1) 300 ms^–1

(2) 310 ms^–1

(3) 320 ms^–1

(4) 330 ms^–1

Two sound sources when sounded simultaneously produce four beats in 0.25 seconds. The difference in their frequencies must be :

(1) 4

(2) 8

(3) 16

(4) 1

Two strings X and Y of a sitar produce a beat frequency 4 Hz. When the tension of the string Y is slightly increased the beat frequency is found to be 2 Hz. If the frequency of X is 300 Hz, then the original frequency of Y was :

(1) 296 Hz

(2) 298 Hz

(3) 302 Hz

(4) 304 Hz

Two vibrating tuning forks produce progressive waves given by $Y_1=4\sin 500\pi t$ and $Y_2=2\sin 506\pi t.$ Number of beats produced per minute is :

(1) 360

(2) 180

(3) 3

(4) 60

The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency :

(1) 10 Hz

(2) 360 Hz

(3) 216 Hz

(4) 6 Hz