The time of reverberation of a room A is one second. What will be the time (in seconds of reverberation of a room, having all the dimensions double of those of room A ?

Which one of the following statements is true ?

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

The phase difference between two waves. represented by
y₁ = 10^$$-$$6 sin[100t + (x/50) + 0.5] m
y₂ = 10^$$-$$6 cos[100t + (x/50)] m,
where x is expressed in metres and t is exressed in secondss, is approximately.