Question

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 λ and.f, respectively. The apparent frequency and wavelength recorded by the observer are respectively.

(a) 1.2 f. 1.2 λ  

(b) 1.2.f,λ  

(c) f, 1.2 λ  

(d) 0.8.f, 0.8 λ  

Answer 1

Correct option   (b) 1.2.f,λ  

Explanation:

Apparent frequency, f,

Wavelength does not change by motion of observer