Q. A tuning fork arrangement (pair) produces beats/s with one fork of frequency . A little wax is placed on the unknown fork and it then produces beats/s. The frequency of the unknown fork is :

 4137  195 AIEEEAIEEE 2002Waves Report Error

Solution:

The tuning fork of frequency is producing 4 beats/s with the unknown tuning fork i. e., the frequency difference between them is 4 .Therefore, the frequency of unknown tuning fork or
On placing a little wax on unknown tuning fork, its frequency decreases but now the number of beats produced per second is 2 i.e., the frequency difference now decreases. It is possible only when before placing the wax, the frequency of unknown fork is greater than the frequency of given tuning fork. Hence, the frequency of unknown tuning fork