Two strings of identical material and radius are stretched with the same tension with their ends fixed,but one string is 8.0 mm longer than the other.Waves on these strings propagate at 420 m/s.The fundamental frequency of the longer string is 528 Hz.What is the beat frequency when each string is vibrating at its fundamental frequency?
A) 22 Hz
B) 11 Hz
C) 16 Hz
D) 5.5 Hz
E) 27 Hz

Question

Quizplus · Accepted Answer

The fundamental frequency is inversely proportional to the length of the string. Since the longer string is 8.0 mm longer, the shorter string will have a slightly higher frequency. The difference in frequencies (beat frequency) is half of the frequency difference due to the 8.0 mm length difference, which is 11 Hz.

Two Strings of Identical Material and Radius Are Stretched with the Same