A point source emits sound equally in all directions in a nonabso… - Vidyadip

MCQ

A point source emits sound equally in all directions in a nonabsorbing medium, Two points $P$ and $Q$ are at distance of $2 \mathrm{~m}$ and $3 m$ respectively from the source. The ratio of the intensities of the waves at $P$ and $Q$ is

✓
$9: 4$
B
$2: 3$
C
$3: 2$
D
$4: 9$

✓

Answer

Correct option: A.

$9: 4$

Intensity $\propto \frac{1}{\text(Distance)^2}\Rightarrow\frac{I_1}{I_2}=\left(\frac{d_2}{d_1}\right)^2=\left(\frac{3}{2}\right)^2=\frac{9}{4}$.

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