Class 11 NEET Physics Waves Questions Questions

The situation as shown in the figure.
Here,
Speed of listener,vL=1ms−1
Speed of sound,v=330ms−1
Frequency of each source, v=660Hz
Apparent frequency due to P,
v′=

v(v−vL)

v

Apparent frequency due to Q,
v"=

v(v+vL)

v

Number of beats heard by the listener per second is
v"−v′=

v(v+vL)

v

−v

(v−vL)

v

=

2vvL

v

=

2×660×1

330

=4