Wave Mechanics Question 895

Question: A tuning fork whose frequency as given by manufacturer is 512 Hz is being tested with an accurate oscillator. It is found that the fork produces a beat of 2 Hz when oscillator reads 514 Hz but produces a beat of 6 Hz when oscillator reads 510 Hz. The actual frequency of fork is

[MNR 1979; RPMT 1999]

Options:

A) 508 Hz

B) 512 Hz

C) 516 Hz

D) 518 Hz

Show Answer

Answer:

Correct Answer: C

Solution:

The tuning fork whose frequency is being tested produces 2 beats with oscillator at 514 Hz, therefore, frequency of tuning fork may either be 512 or 516. With oscillator frequency 510 it gives 6 beats/sec,

Therefore frequency of tuning fork may be either 516 or 504.

Therefore, the actual frequency is 516 Hz which gives 2 beats/sec with 514 Hz and 6 beats/sec with 510 Hz.