Question

A tuning fork of frequency 250 Hz is vibrating at one end of a tube as shown in the figure. If maximum sound is heard at the other end, then the velocity of the waves will be

A. 336 m/s
B. 672 m/s
C. 168 m/s
D. 285 m/s

Answer 1

Correct Answer - D
Path difference `= pi r - 2r`
Path difference for maximum sound is `lamda`,
`lamda = r [pi -2]`
`= [3.14 -2] xx 1`
`lamda = 1.14`
`v = n lamda`
`= 250 xx 1.14 = 285.00`
`v = 285 m//s`