Question

The apparent frequency is `f_(1)` when a souece of sound approches a stationary obsever with a speed u and `f_(2)` when the observe approaches the stationary source with same speed. If v is the velocity of sound, then
A. `f_(1)=f_(2)`
B. `f_(1) gt f_(2) if u ltv`
C. `f_(2) gt f_(1) if u ltv`
D. `f_(2) gt f_(1) if u ltv`

Answer 1

Correct Answer - D
`f_(1)=((v)/(v-v_(s)))f=((v)/(v-v))f=[((1)/(1-u/v))]f`
When observer approaches towards the source
`f_(2)=((v+v_(o))/(v))f=((v+u)/(v))f=(1-u/v)f`
`therefore" "f_(2) gt f_(1)`