Question

In expressing sound intensity, we take ${10}^{-12}W{m}^{-2}$ as the reference level. For ordinary conversion, the intensity level is about ${10}^{-6}W{m}^{-2}$. Expressed in decibel, this is :

• A. ${10}^6$
• B. $6$
• C. $60$
• D. $lo{g}_e\left({10}^6\right)$

Answer 1

Answer: (C)

$60$

Intensity of reference level $I_o={10}^{-12}W{m}^{-2}$

Measured intensity $I={10}^{-6}W{m}^{-2}$

Using $L=10{\log }_{10}\frac{I}{I_o}$ decibels

$\therefore$ $L=10{\log }_{10}\frac{{10}^{-6}}{{10}^{-12}}$ decibels

Or $L=10lo{g}_{10}{10}^6=10\times 6=60$ decibels