In the figure shown below, a source of sound having power `12xx10^-6W` is kept at `O`, which is emitting sound waves in the directions as shown. Two surfaces are labelled as 1 and 2 having areas `A_1=2xx10^3m^2` and `A_2=4xx10^3m^2`, respectively
Q. Let the areas of the eardrums of persons `A` and `B` be `A_A=2mm^2` and `A_B=4mm^2`, respectively. Then who will hear a quiter sound?

Options

A. A will hear a quiter sound.
B. B will hear quiter sound
C. Both will hear the same sound.
D. Cannot say anything.

Answer

C

Explanation

Power received by `A's` ear is `I_1xxA_A=12xx10^(-15)W`
Power received by B's ear is `=I_1xxA_A=12xx10^(-15)W` so, both hear the same sound.