Question

A sound absorber attenuates the sound level by 20 dB. The intensity decreases by a factor of

• A. 100
• B. 1000
• C. 10000
• D. 10

Answer 1

The correct option is A 100

From the formula: $\Delta L=10{\log }_{10}\frac{I_1}{I_2}$

We are given: $\Delta L=20dB$

Substitute this value in the formula:

$20=10{\log }_{10}\frac{I_1}{I_2}$

${\log }_{10}\frac{I_1}{I_2}=2$

$\frac{I_1}{I_2}={10}^2=100$