A tuning fork produces 4 beats per second with another tuning fork of frequency 256 Hz. The first one is now loaded with a little wax and the beat frequency is found to increase to 6 per second. What was the original frequency of the tuning fork ?

Answer

B

Explanation

A tuning fork produces 4 beasts with as known tuning fork whose frquency
=256Hz
So the frequency of unknown tuing fork `=either 256
`=4-252 or 256+4 `
`=260 Hz`
Now as the first one is loaded its mass/unit length increases. So its frequency decreases.
As it produces 6 beats now origoN/Al frequency must be 252 Hz.
260 Hz is not possible as on decreasing the frequency the beats decrease which is not allowed here.