If the separation between the screen and the source is increased by $2\%$,what would be the effect on the intensity?

As a wave propagates,which of the following statements is correct?

$A$ stationary point source of sound emits sound uniformly in all directions in a non-absorbing medium. Two points $P$ and $Q$ are at a distance of $4 \ m$ and $9 \ m$ respectively from the source. The ratio of amplitudes of the waves at $P$ and $Q$ is

The intensity of a progressing plane wave in a loss-free medium is

$A$ stone is dropped in still water,creating a circular wave pattern that spreads outward. If $r$ is the distance from the center of this circular pattern,the amplitude of the wave is proportional to ........

$A$ point source is emitting sound waves of intensity $16 \times 10^{-8} \text{ W m}^{-2}$ at a distance of $1 \text{ m}$ from the source. The difference in intensity (magnitude only) at two points located at distances of $2 \text{ m}$ and $4 \text{ m}$ from the source respectively will be . . . . . . $\times 10^{-8} \text{ W m}^{-2}$.