wave_mechanics Beats Question 14

Question: Two tuning forks A and B vibrating simultaneously produce 5 beats. Frequency of B is 512. It is seen that if one arm of A is filed, then the number of beats increases. Frequency of A will be

[MP PMT 1991]

Options:

A) 502

B) 507

C) 517

D) 522

Show Answer

Answer:

Correct Answer: C

Solution:

After filling frequency increases, so $ n _{A} $ decreases (¯).

Also it is given that beat frequency increases (i.e., x ­) Hence nA¯ ? nB = x­ …

(i) Correct nB ? nA­ = x­ …

(ii) Wrong

Therefore nA = nB + x = 512 + 5 = 517 Hz.