Q. A stone thrown into still water, creates a circular wave pattern moving radially outwards. If $r$ is the distance measured from the centre of the pattern, the amplitude of the wave varies as
A) $r^{- 1/2}$
B) $r^{- 1}$
C) $r^{- 2}$
D) $r^{- 3/2}$
Explanation
(b) $I = \frac{P}{4\pi r^{2}} \propto A^{2} \Rightarrow A \propto \frac{1}{r}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.