IF A is the amplitude of the wave coming from a point source at distance r then

Options

A. `A prop^(-2)`
B. `A prop^(-1)`
C. `A prop^(2)`
D. `A prop^(1)`

Answer

B

Explanation

For a point source `I prop (1)/(r^(2))`
and `A prop sqrt(I)`
`:. A prop sqrt((1)/(r^(2))) or A prop (1)/(r)`