a tuning fork of unknown frequency gives 4 beats with a tuning fork of freqency 310 Hz. it gives the same no. of beats on filing. find the unknown frequency

Let the unknown frequency be f.

So, before filling f – 310 = 4 Hz => f = 314 Hz

And, after filling, 310 – f = 4 Hz => f = 306 Hz

Thus, the required frequency is 314 Hz.