STANDARDPhysics-Waves

STANDARD Physics Beat Frequency MCQ Question

Type: MCQ-conceptual-Medium-Class 11

Two sitar strings A and B are slightly out of tune and produce beats of frequency 5 Hz. When the tension in the string B is slightly increased, the beat frequency is found to reduce to 3 Hz. If the frequency of string A is 427 Hz, the original frequency of string B is

Question diagram
A

422 Hz

B

424 Hz

C

430 Hz

D

432 Hz

Correct Answer

Option A

Detailed Explanation

The frequency of string A, vₐ = 427 Hz. Let original frequency of string B be vᵦ. vᵦ = (vₐ ± 5) Hz = 432 Hz or 422 Hz. Increase in the tension of a string B, increases its frequency. If vᵦ = 432 Hz, a further increase in vᵦ would increase the beat frequency, which is not given. If vᵦ = 422 Hz, a further increase in vᵦ decreases the beat frequency, which matches the question. Thus, the original frequency of string B is 422 Hz.

Found an issue with this question?