Question

The wavelength of the sound produced by a source is 0.8 m if the source moves towards the stationary listener at 32 m/s what is the apparent wavelength of sound if velocity of sound is 320 m/s

Answer 1

Answer:

0.72m

Explanation:

From Doppler's effect we know, when source is moving,

apparent wavelength=

$\frac{320 - 32}{320} \times 0.8$

Answer 2

The apparent wavelength of sound is 0.72 m.

 Given,

  Actual wavelength of sound(lambda) = 0.8 m

  Velocity of source of sound = 32 m/s

   Velocity of sound in air = 320 m/s

  Using Doppler's effect for the case when source is moving stationary listener, apparent wavelength is given by

     $(lambda)'=(lambda)(\frac{v-v_{s}}{v})$

                     $=0.8(\frac{320-32}{320})$

                     $=0.8(\frac{288}{320})$

                     $=(0.8)(0.9)$

                     $=0.72m$

∴ The apparent wavelength decreases when source of sound is moving towards stationary listener.