A bat emitting an ultrasonic wave of frequency 4.5 × 104 Hz flies at a speed of 6 rn/s between two parallel walls. Find the two frequencies heard by the bat and the beat frequency between the two. The speed of sound is 330 m/s.
Let us assume that the bat is flying from wall B to wall A.
The given parameters are,
Vs=6ms-1
f0=4.5x104 Hz
The apparent frequency received by wall A will be,
Now the wall A will act like a source and the bat is moving towards A. So, the apparent frequency will be,
Now the apparent frequency received by the wall B will be,
Now, wall be will act like a source and the apparent frequency received by the bat will be,
Now the beat frequency will be,