$A$ 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 ........

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

With the propagation of a longitudinal wave through a material medium,the quantities transmitted in the propagation direction are

If the pressure amplitude in a sound wave is tripled,then the intensity of sound is increased by a factor of

$A$ musical instrument $P$ produces sound waves of frequency $n$ and amplitude $A_P$. Another musical instrument $Q$ produces sound waves of frequency $\frac{n}{4}$. The waves produced by $P$ and $Q$ have equal energies. If the amplitude of waves produced by $P$ is $A_P$,the amplitude of waves produced by $Q$ will be: (in $A_P$)

The amplitudes of two waves are in the ratio $5 : 2$. If all other conditions for the two waves are the same,what is the ratio of their energy densities?