Question

The ratio of the amplitude of two waves is 3:4. What is the ratio of their intensities?

Answer 1

We know that intensity is proportional to square of the amplitude.
$\frac{I_1}{I_2}=\{\frac{A_1}{A_2}{\}}^2=\{\frac{3}{4}{\}}^2=\frac{9}{16}$