There is a long linear source of sound whose power is $P$ and length is $L$. At point $A$,the sound level is $80 \ dB$. Then at point $B$,the sound level will be .... $dB$.

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

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

If the ratio of intensities of two waves is $1 : 25$,then the ratio of their amplitudes will be

$A$ point source emits sound equally in all directions in a non-absorbing medium. Two points $P$ and $Q$ are at distances of $2 \ m$ and $3 \ m$ respectively from the source. The ratio of the intensities of the waves at $P$ and $Q$ is:

$A$ transverse wave is passing through a stretched string with a speed of $20 \ m/s$. The tension in the string is $20 \ N$. At a certain point $P$ on the string,it is observed that energy is being transferred at a rate of $40 \ mW$ at a given instant. Find the speed of point $P$.