A sound wave of frequency `f` travels horizontally to the right. It is reflected from a large vertical plane surface moving to left with a speed `v`. The speed of sound in medium is `C`

Options

A. the frequency of the reflected wave is `[(c+v)/(c-v)]`
B. the wavelength of the reflected wave is `[c/n][(c+v)/(c-v)]`
C. the number of waves striking the surface per second is `[(c+v)/c]xx n`
D. the number of beats heard by a stationary listerner to the left to the reflecting surface is `(nv)/(c-v)`

Answer

C

Explanation

Large vertical phane acts as listerner moving towards source with a velocity v.
`:. n'=((c+v)n)/c`
This is the number of waves strinking the surface per second.