A is singing a note and at the same time B is singing a note with exactly one eighth the frequency of the note of A. The energies of two sounds are equal, the amplitude of the note of B is

Options

A. Same that of A
B. Twice as that of A
C. Four times as that of A
D. Eight times as that of A

Answer

D

Explanation

Energy `prop(A)^(2)(f)^(2)`
`implies (A_(A))/(A_(B))=(f_(B))/(f_(A))implies(A_(B))/(A_(A))=(8)/(1)`
`implies A_(B)=8A_(A)`.