Question

Intensity level of sound whose intensity is ${10}^{-8}w{m}^{-2}$ is ______ dB.

• A. $8$
• B. $4$
• C. $40$
• D. $80$

Answer 1

The correct option is C $40$

Given : $I={10}^{-8}$ $W/m^2$

Intensity level of sound $L=10{\log }_{10}\frac{I}{I_o}dB$ where $I_o={10}^{-12}$ $W/m^2$

OR $L=10{\log }_{10}\frac{{10}^{-8}}{{10}^{-12}}dB$

OR $L=10{\log }_{10}{10}^{4}dB$

OR $L=10\times 4=40dB$