A source of sound producing wavelength 50 cm is moving away from a stationary observer with `(1/5)^(th)` speed of sound. Then what is the wavelength of sound received by the observer?

Options

A. 55 cm
B. 40 cm
C. 60 cm
D. 70 cm

Answer

C

Explanation

Here, wavelength of the source, `lambda=50cm`
Speed of the sound = v Speed of the source, `v_(s)=(1)/(5)v`
As the source is moving away from the stationary observer, therefore the wavelength of sound received by the observer is
`lambda.=((v+v_(s)))/(v)lambda=((v+(1)/(5)v))/(v)lambda`
`=(6)/(5)lamda=(6)/(5)xx50cm=60cm`