Question

If the pressure amplitude in a sound wave is tripled, then the intensity of sound is increased by a factor of:

• A. 6
• B. 3
• C. 9
• D. $\sqrt{3}$

Answer 1

Answer: (C)

9

Answer 2

From the relation intensity $\propto$ (amplitude)2 $I\propto {{a}^{2}}$ Hence, $\frac{{{I}_{1}}}{{{I}_{2}}}=\frac{a_{1}^{2}}{a_{2}^{2}}=\frac{{{a}^{2}}}{{{(3a)}^{2}}}=\frac{1}{9}$ so, ${{I}_{2}}=9I$