Question

If the intensity of sound is to be increased 4 times, by how many times should the amplitude be increased?

• A. 4
• B. 2
• C. 8
• D. 16

Answer 1

The correct option is B 2

Intensity (I) of a wave is proportional to the square of the amplitude (A).
$I\propto A^2$

Intensity is to be increased four times.
$I_2=4I_1$

$\frac{I_2}{I_1}=\frac{A_2^2}{A_1^2}=4$
${\left(\frac{A_2}{A_1}\right)}^2=4$
$\frac{A_2}{A_1}=2$