An observer moves towards a stationary source of sound with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency?

Options

A. 0.2
B. 0.05
C. `0.5%`
D. zero

Answer

A

Explanation

When observer moves towards stationary source then apparent frequency
`n' = [(v +v_(0))/(v)]n = [(v +(v//5))/(v)]n = (6)/(5)n = 1.2n`
Increment in frequency = 0.2 n so percentage change in frequency `= (0.2n)/(n)xx100=20 %`