Question

A tuning fork of unknows frequency makes three beats per second with a standard fork of frequency `384 H_(Z)`. The beat frequency decreases when a small piece of wax is put on a prong of the first fork. What is the frequency of this fork?

Answer 1

Correct Answer - C
By putting wax on first tuning fork, its frequency will decrease.
Beat frequency is also decreasing. Hence,
`f_(1) gt f_(2)`
`:. f_(1) - f_(2) = 3`
or `f_(1) = 3 + f_(2) = 3 + 384`
`= 387 H_(Z)`