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

As a wave propagates:

If the ratio of the amplitude of two waves is $4:3$,then the ratio of their maximum and minimum intensity is:

The intensity ratio of two waves is $1 : 16$. The ratio of their amplitudes is

$A$ travelling wave is partly reflected and partly transmitted from a rigid boundary. Let $a_i, a_r$ and $a_t$ be the amplitudes of the incident wave,reflected wave,and transmitted wave,and $I_i, I_r$ and $I_t$ be the corresponding intensities. Choose the correct alternative.

The intensity level at a distance of $200 \ cm$ from a sound source is $80 \ dB$. If there is no loss of acoustic power in the air and the threshold intensity of hearing is $10^{-12} \ W/m^2$,what is the intensity level at a distance of $400 \ cm$ from the source (in $dB$)?