## Question

Two tuning forks *A* and *B* produce 10 beats per second when sounded together. On slightly loading fork *A* with a little wax, it was observed that 15 beats are heard per second. If the frequency of fork *B* is 480 Hz, what is the frequency of fork *A* before it was loaded?

### Solution

470 Hz

Let *V*_{1} be the frequency of *A* and *V*_{2} that of fork *B*. There are two possibilities (a) *V*_{1} > *V*_{2} and (b) *V*_{1} < *V*_{2}.

On loading fork A its frequency decreases. In order words, *V*_{1} decreases.

should also decrease. But *V _{b}* increase to 15 beats/s. Hence

*V*

_{1}is not greater than

*V*

_{2}.

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