The speed of propagation of a transverse wave on a 2.0-m long string fixed at both ends is 200 m/s.Which one of the following is not a resonant frequency of this string?
A)25 Hz
B)50 Hz
C)100 Hz
D)200 Hz

Question

Quizplus · Accepted Answer

The resonant frequencies of a string fixed at both ends are given by the formula f_n = n(v/2L), where n is a positive integer, v is the speed of the wave, and L is the length of the string. For this string, f_n = n(200/4) = 50n Hz. The resonant frequencies are multiples of 50 Hz (50, 100, 150, 200, etc.). 25 Hz is not a multiple of 50 Hz, so it is not a resonant frequency.

The Speed of Propagation of a Transverse Wave on a 2.0-M