Consider the droppler effect in two cases. In the first case an observer moves towards a stationary sound-source, with a speed `V_(1)`. In the second case, the observer is at rest, and the source moves towards the observer with the same speed `V_(1)`. Then the frequency heard by the observer

Options

A. will be the same in both cases
B. will be more in the second case than in the first case
C. will be less in the second case than in the first case
D. will be less than the actual frequency in both cases

Answer

B

Explanation

For case (1), `n_(1) = ((V + V_(1))/(V)) n`
For case (2), `n_(2) = ((V)/(V - V_(1)))n`
Both `n_(1) and n_(2) gt n " but " n_(2) gt n_(1)`
(Verify it by taking actual values. e.g V = 330 m/s `V_(1) = 50m//s`)