Question

If two tuning forks A and B are sounded together , they produce 4 beats per sec. A is then slightly loaded with wax and same no. of beats/sec. are produced again. If frequency of A is 256, the frequency of B would be

• A. 250
• B. 262
• C. 252
• D. 260

Answer 1

The correct option is C 252

Since four beats per second are heard when A and B are sounded together, $256Hz-\nu =\pm 4Hz$

where $\nu$ is the frequency of B.

Now, loading with wax decreases the frequency of tuning fork.

Waxing tuning fork A would mean the frequency of A has reduced such a way that it again produces 4 beats per second with B. Thus it is now lower than B by $4Hz$ and initially it was higher than B by $4Hz$.

$⟹256Hz-\nu =4Hz$

$⟹\nu =252Hz$