$A$ 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 ........

The intensity of sound after passing through a slab decreases by $30\%$. On passing through two such slabs,the intensity will decrease by ..... $\%$

The relation between time and displacement for two particles is given by
${y_1} = 0.06 \sin 2\pi (1.04t + {\phi _1})$
${y_2} = 0.03 \sin 2\pi (1.04t + {\phi _2})$
The ratio of the intensity of the waves produced by the vibrations of the two particles will be

Two waves are represented by
$y_1 = 5 \sin 2 \pi(75 t - 0.25 x)$
$y_2 = 10 \sin 2 \pi(150 t - 0.50 x)$
The intensity ratio $\frac{I_1}{I_2}$ of the two waves is

On getting reflected at a surface,the intensity of sound is found to be decreased by $20 \%$. If $A$ be the amplitude of the incident sound waves,then the amplitude of reflected sound waves is

The displacement-time graphs for two sound waves $A$ and $B$ are shown in the figure. The ratio of their intensities $I_A/I_B$ is equal to: