A source of sound of frequency 1000 Hz moves to the right with a speed of `32(m)/(s)` relative to the ground. To its right there is a reflecting surface moving to the left with a speed of `64(m)/(s)` relative to the ground. Take the speed of `64(m)/(s)`. Relative to the ground. Take the speed of sound in air to be `332(m)/(s)` and find
(a) The wavelength of the sound emitted in air by the source,
(b) the number of waves per second arriving at the reflecting surface,
(c ) The speed of the reflected waves and
(d) The wavelength of the reflected waves.

Answer

A, B, C, D

Explanation

(a) Wavelength of sound ahead of the source is
`lambda' = (nu - nu_(s)/(f)) = (332 - 32)/(1000) = 0.3 m`
(b) `f' = f(nu + nu_(0))/(nu - nu_(s)) = 1000 ((332 + 64)/(332 - 32))`
`= 1320 H_(Z)`
(c ) Speed of reflected wave will remain `332 m//s` .
(d) Wavelength of reflected wave.
`lambda" = (nu - nu_(0))/(f') = (332 - 64)/(1320)`
`= 0.2 m`