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 mwdium is `C`

Options

A. (a) The number of wave strinking the surface per second is `f((c + v)/(c ))`
B. (b) The wavelength of reflected wave is `(c(c-v))/(f(c+v))`
C. ( c ) The frequency of the reflected wave is `f(((c+v))/((c-v)))`
D. (d) The number of beats heard by a stationary listener to the left if the reflecting surface is `(vf)/(c-v)`

Answer

A, B, C

Explanation

(a,b,c) Frequency of reflected wave is `f" = f((c + c)/(c - v))`
rArr Beat freq. `= f" - f = (2v)/(c - 1)`.
Wavelength of reflacted wave = ( c )/(f") =(c(c - v))/(f( c + v))`