The wavelength of two nodes in air are `36/195` m and `36/193` m. Each node products `10 beats//s` seprately with a third node of fixed frequency. The velocity of sound in air in `m//s` is

Options

A. 330
B. 340
C. 350
D. 360

Answer

D

Explanation

Beat frequency =`n_1-n_2`
Let, n be the frquency of third node then,
`implies n=v/lambda`
`n_1-n=10 and n-n_2=10`
`(195v)/36-n=10` (1)
`n-(195v)/36=10` (2)
Adding equations (1) and(2)
`(2v)/36=20`
`:. v=360ms^-1`