A sound wave of frequency n travels horizontally to the right. It is reflected from a large vertical plane surface moving to the left with a speed v. The speed of sound in the medium is c, then [IIT 1995; BCECE 2005]

• A.            The frequency of the reflected wave is \[\frac{\nu (c+v)}{c-v}\]
• B.            The wavelength of the reflected wave is \[\frac{c(c-v)}{\nu (c+v)}\]
• C.            The number of waves striking the surface per second is \[\frac{\nu (c+v)}{c}\]
• D.            The number of beats heard by a stationary listener to the left of the reflecting surface is \[\frac{\nu \ v}{c-v}\]