Question

If the ratio of amplitudes of two sound waves is $\frac{1}{3}$, then what should be the ratio of their intensities?

• A. $3$
• B. $9$
• C. $1/3$
• D. $1/9$

Answer 1

The correct option is D $1/9$

Intenisty $\left(I\right)$ depends on the square of amplitude $\left(A\right)$

$I\alpha A^2$

$\frac{I_1}{I_2}={\left(\frac{A_1}{A_2}\right)}^2$

$\frac{I_1}{I_2}={\left(\frac{1}{3}\right)}^2=\frac{1}{9}$

Hence, the ratio of the intensities is $\frac{1}{9}$