Question

The wave length of the sound produced by a
source is 0.8m. If the source moves towards
the stationary listener at 32 ms , what is the
apparent wave length of sound if the velocity
of sound is 320 ms !

1) 0.32 m
2) 0.4 m
3) 0.72 m
4) 0.80 m​

Answer 1

Hello Mate,

Here is your answer,

Given:

• Wave Length = 0.8m

• The source moves TOWARDS the stationary listener at 32 m/s

• Velocity of sound = 330 m/s

To find:

• Apparent wave length of sound

Formula Used:

As the source is moving towards the observer, we should use formula:-

$x = y (\frac{u - u_{s} }{u} )$

Where,

x => apparent wave length of sound

y => wave length of sound

u => velocity of sound

$u_{s}$ => velocity of source

Solution:

By substituting values in the formula we get,

0.8 (330 - 32)

330

= 0.8 x 0.9

= 0.72m

Hope it helps:)