An observer moves towards a stationary source of sound with a speed `((1)/(5))`th of the speed of sound. The wavelength and frequency of the source emitted are `lamda` and f, respectively. The apparent frequency and wavelength recorded by the observer are, respectively.

Options

A. `1.2f,lamda`
B. `f,1.2lamda`
C. `0.8f,0.8lamda`
D. `1.2f,1.2lamda`

Answer

A

Explanation

`n'=(v+v_0)/(v)n=(v+(v)/(5))/(v).f=(6)/(5)f=1.2f` and since the source is stationary, so wave length remains unchanged for observer.