Given:
Speed of bat v = 6 ms−1
Frequency of ultrasonic wave f = 4.5 × 104 Hz
Velocity of bird = 6 ms−1
Let us assume that the bat is flying between the walls X and Y.
Apparent frequency received by the wall Y is
Now, the apparent frequency received by the bat after reflection from the wall Y is given by:
Frequency of ultrasonic wave received by wall X:
The frequency of the ultrasonic wave received by the bat after reflection from the wall X is
Beat frequency heard by the bat is