A point source emits sound equally in all direction in a non-absorbing medium. Two points P and Q are at distance of 2 and 3 m respectively from the source. The ratio of the intensities of the wave at P and Q is.

Question

Dr. Abubacker · Accepted Answer

(a) The average power per unit area that is incident perpendicular to the direction of propagation is called the intensity, i.e.,
$I = \frac{P}{4\pi r^{2}}$
Or
$I \propto \frac{I}{r^{2}}$
Or
$\frac{I_{2}}{I_{2}} = \left( \frac{r_{2}}{r_{1}} ight)^{2}$
Here, $r_{1} = 2m,\ r_{2} = 3m$
$	herefore\frac{I_{1}}{I_{2}}\  = \left( \frac{3}{2} ight)^{2} = \frac{9}{4}$

Q. A point source emits sound equally in all direction in a non-absorbing medium. Two points P and Q are at distance of 2 and 3 m respectively from the source. The ratio of the intensities of the wave at P and Q is.

Explanation

Reviewed by Dr. Abubacker

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