Two waves represented by the following equations are travelling in the same medium: $y_1 = 5\sin 2\pi (75t - 0.25x)$ and $y_2 = 10\sin 2\pi (150t - 0.50x)$. The intensity ratio $I_1/I_2$ of the two waves is:

$A$ 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

If the amplitude of sound is doubled and the frequency is reduced to one-fourth,the intensity of sound at the same point will be

$A$ sound source emits sound waves in a uniform medium. If energy density is $E$ and maximum speed of the particles of the medium is ${v_{\max }}$,the plot between $E$ and ${v_{\max }}$ is best represented by

If the amplitude of waves at a distance $r$ from a point source is $A$,the amplitude at a distance $2r$ will be

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