Two identical tuning forks vibrating at the same frequency 256 Hz are kept fixed at some distance apart. A listener runs between the forks at a speed of 3.0 m/s so that he approaches one tuning fork and recedes from the other (figure 16-E10). Find the beat frequency observed by the listener. Speed of sound in air = 332 m/s.


Let us assume that the fork approaching is A and the other one is B. Now, as the observer is moving the frequency from A will be given by,



Similarly, from B,



Hence, the beat frequency will be,





Putting the values,



1