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

The intensity of a sound wave while passing through an elastic medium falls by $10\%$ as it covers $1 \ m$ distance through the medium. If the initial intensity of the sound wave was $100 \ dB$,its value after it has passed through $3 \ m$ thickness of the medium will be .... $dB$.

The clocktower ("ghantaghar") of Dehradun is famous for the sound of its bell, which can be heard, albeit faintly, up to the outskirts of the city $8 \,km$ away. Let the intensity of this faint sound be $30 \,dB$. The clock is situated $80 \,m$ high. The intensity at the base of the tower is ............. $\,dB$.

$A$ spherical source of power $4 W$ and frequency $800 Hz$ is emitting sound waves. The intensity of waves at a distance $200 m$ is

The ratio of intensities of two waves is given by $4:1$. The ratio of the amplitudes 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