Question

The ratio of intensities of two sound waves is $4:9$. The ratio of their amplitudes will

• A. $9:4$
• B. $4:9$
• C. $2:3$
• D. $3:2$

Answer 1

Answer: (C)

$2:3$

Ratio of intensities of two waves is $\frac{I_1}{I_2}=\frac{A_1^2}{A_2^2}=\frac{4}{9}\Rightarrow \frac{A_1}{A_2}=\frac{2}{3}$
Thus the ratio of their amplitudes is $\frac{2}{3}$.