The sound waves of wavelength 5 m and 6 m formed 30 beats in 3 s. The velocity of sound is

Options

A. `300 ms^-1`
B. `310 ms^-1`
C. `320 ms^-1`
D. `330 ms^-1`

Answer

A

Explanation

Frequency `n=V/lambda`
`n_1=V/lambda_1` and `n_2=V/lambda_2`
number of beats per `sec (n_1-n_2)=30/3`
`V/lambda_1-V/lambda_2=10`
`V[1/5-1/6]=10`
`V[1/30]=10`
`:.V=300 m//s`