A tuning fork is sounded above an adjustable length resonating tube (one end closed),which resonates at a length of 0.250 m and again at 0.750 m.What is the frequency of the fork when the speed of sound is taken to be 340 m/s?
A) 340 Hz
B) 680 Hz
C) 1020 Hz
D) 170 Hz

Question

Quizplus · Accepted Answer

The resonating tube with one end closed forms a quarter-wave resonator. The first resonance occurs at 0.250 m (1/4 wavelength) and the second at 0.750 m (3/4 wavelength). The difference between these lengths is 0.500 m, which is half a wavelength. Therefore, the full wavelength is 1.000 m. Using the speed of sound (340 m/s), the frequency is calculated as speed/wavelength = 340 m/s / 1.000 m = 340 Hz.

A Tuning Fork Is Sounded Above an Adjustable Length Resonating