A wall is moving with a velocity u and a source of sound is moving with a velocity u 2 , in the same direction, as shown in the figure. Assume that the sound travels with velocity 10 u , the ratio of incident sound wavelength on the wall to the reflected sound wavelength by the wall is equal to

Step-by-step solution

λ i = Wavelength of the incident sound = 10 u - u 2 f = 19 u 2 f f i = Frequency of the incident sound = 10 u - u 10 u - u 2 f = 18 19 f = f = f r = Frequency of the reflected sound λ r = Wavelength of the reflected sound = 10 u + u f r = 11 u 18 f × 19 = 11 × 19 18 . u f λ i λ r = 19 u 2 f × 18 f 11 × 19 u = 9 11