A stationary source emits sound waves of frequency 500 , Hz. Two … - Vidyadip

MCQ

A stationary source emits sound waves of frequency $500\, Hz$. Two observers moving along a line passing through the source detect sound to be of frequencies $480\, Hz$ and $530\, Hz$. Their respective speeds are, in $m\,s^{-1}$ (Given speed of sound $= 300\, m/s$)

A
$16, 14$
B
$12, 16$
C
$8, 18$
✓
$12, 18$

✓

Answer

Correct option: D.

$12, 18$

d
$ v= \frac{v+v_{0}}{v} v_{0}$

$\Rightarrow v_{0}=\left(\frac{v}{v_{0}}-1\right) v$

$v_{0}=\left(\frac{530}{500}-1\right) 300=18 \mathrm{m} / \mathrm{s}$

$v_{0}=\left|\left(\frac{480}{500}-1\right) 300\right|=12 \mathrm{m} / \mathrm{s}$

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