Question

Frequency of tuning fork $A$ is $256Hz.$ It produces four beats/sec with tuning fork $B.$ When wax is applied at tuning fork $B$ then $6$ beats/sec are heard. By reducing little amount of wax $4$ beats/sec are heard. Frequency of $B$ is :

• A. $250Hz$
• B. $252Hz$
• C. $260Hz$
• D. $256Hz$

Answer 1

The correct option is B $252Hz$

Let the unknown frequency of the tuning fork be x.

So, according to the given data when no waxed, its frequency must be,

$x=256\pm 4$ to produced a beat of $4beats/sec$.

We know, the frequency of a tuning fork decreases as it is waxed.

So, to produce $6beats/s$, after being waxed, the frequency of the tuning fork must be

$x=256-4$

$x=252Hz$

Hence, the frequency of $B$ is $252Hz$