Question

A long glass tube is held vertically in water. A tuning fork is struck and held over the tube. Strong resonances are observed at two successive lengths `0.50 m` and `0.84 m` above the surface of water. If the velocity of sound is `340 m//s`, then the frequency of the tuning fork is
A. 128Hz
B. 256Hz
C. 284Hz
D. 500Hz

Answer 1

Correct Answer - D
`n=(v)/(2(l_2-l_1)) = (340)/(2(0.84 - 0.50))`
`=(350)/(2[0.34]) = (34000)/(34xx2) = (1000)/(2) = 500Hz`