Question

The pressure amplitude in a sound wave is tripled and frequency halved, the intensity of the sound is increased by a factor of

• A. 1.25
• B. 3.25
• C. 9.25
• D. 2.25

Answer 1

The correct option is D 2.25

Intensity depends on amplitude and also on frequency

$I=\frac{1}{2}\rho {\omega }^2{A}^{2}v$

$I^{{}^{\prime }}=\frac{1}{2}\rho (\frac{\omega }{2}{)}^2\times (3A{)}^{2}v=2.25I$