Two waves of the same pitch have amplitudes in the ratio 1:3. What will be the ratio of their:

(i) Intensity is the measure of loudness.
Loudness ∝ (amplitude) ²

$$\begin{aligned}\therefore \frac{L_1}{L_2} = \Big(\frac{a_1}{a_2}\Big)^2 \\[0.5em] \Rightarrow \frac{L_1}{L_2} = \Big(\frac{1}{3}\Big)^2 \\[0.5em] \Rightarrow \frac{L_1}{L_2} = \frac{1}{9}\end{aligned}$$

Therefore, Ratio of intensities is 1:9

(ii) Ratio of frequencies is 1:1 (same frequency as pitch is same for both waves).