As a wave propagates

Options

A. the wave intensity remains constant for a plane wave
B. the wave intensity decrease as the inverse square of the distance frome the source for a spherical wave
C. the wave intensity decrese as the inverse of the distance frome a line source
D. total power of the spherical wave over the spherical surface centred at the source remains constant at all the times

Answer

a., b., c., d.

Explanation

For a point source
`Iprop(1)/(r^(2)`
for a line source
`Iprop(1)/(r )`
for a plane wave, intensity remains same because there is no spreading of wave.