Question

A, B and C are three tuning forks. Frequency of Ais
300 Hz. 10 beats per second are produced on sounding
forks A and B together whereas when B and C are
sounded together, then 7 beats per sound are produced.
On loading the arm of tuning fork A with wax it produces
7 beats per second with B and 2 beats per sec with C. Find
the frequencies of B and C.


Please provide me it's solution.
ANSWER : B-290Hz, C-295Hz. ​

Answer 1

Answer:

The frequency of B can be 355 Hz or 345 Hz, When a wax is put on A its frequency decreases.

as the number of beats heard is decreasing, the new value of frequency of A must be closer to B, which implies frequency of B must be 345 Hz. and new frequency of A is 347 Hz.

The beats heard when B and C vibrates is 4 per second, which implies frequency of C must be 341 or 349 Hz.

the beats heard between A and C after A is waxed, is 6 Hz. Which implies frequency of C can be 341 Hz or 353 Hz.

Taking common of above two frequency of C is 341 Hz.

Hence frequency of B and C is 345, 341 Hz.