A sound wave of frequency `f` travels horizontally to the right . It is teflected from a larger vertical plane surface moving to left with a speed `v`. the speed of sound in medium is `c`
(a) The number of waves striking the surface per second is `f(c + upsilon)/(c)`
(b) The wavelength of reflected wave is `(c(c-upsilon))/(f(c+upsilon))`
(c) The frequency of the reflected wave is ` f((c+upsilon))/((c+upsilon))`
(d) The number of beats heard by a stationary listener to the left of the reflecting surface is `(upsilon f)/(c - upsilon)`

Options

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

Answer

A, B, C

Explanation

No of wave striking the surface `f = f((c+v)/(c))`
`f=f ((c)/(c-v)) = f((c+v)/(c-v))`
`lamda = (c)/(f') = (c)/(f) ((c-v)/(c+v))`