A tuning fork is used to produce resonance in glass tuve. The length of the air column in the tube can be adjusted by a variable piston. At room temperature of `27^@C` two succesive resonance are produced at 20 cm and 73 cm column length. If the frequency of the tuning fork is 320 Hz. the velocity of sound is air at `27^(@)C` is

Options

A. 350 m/s
B. 339 m/s
C. 330 m/s
D. 300 m/s

Answer

B

Explanation

`l_(1) + e = (lambda)/(4)`
`lambda_(2) + e = (3 lambda)/(4)`
Solving the above two equations we get `lambda = 2 (l_(2) - l_(1))`
We know that `upsilon = f lambda`
`upsilon = 2 f [l_(2) - l_(1)] = 2 xx 320 xx [73 - 20] xx 10^(-2)`
= 339 m/s
Hence option (b) is correct.