Two waves of wavelength 2.00 m and 3.03 m produce 20 beats in 5 seconds. Calculate the speed of sound in gas.

Explanation

We are given,
`lambda_(1) = 2.0 m, lambda_(2) = 3.03 m`
Beat frequency, `v_(1) - v_(2) = 20/5 = 4`
We know that, `u = v/lambda`
Therefore, `v/lambda_(1) - v/lambda_(2)=4` or `v(1/lambda_(1)-1/lambda_(2)) =4` or `v(1/2 -1/3.03) = 4`
`v = (4 xx 6.06)/1.03 = 23.53 ms^(-1)`