Question

A sound pressure level of 40 decibels is equivalent to a sound pressure of:

• A. 0.002 Pa
• B. 0.04 Pa
• C. 20 Pa
• D. 40 Pa

Hint:

Decibels measure sound intensity on a logarithmic scale, relative to a reference pressure (P0 = 2 × 10−5 Pa).

Answer 1

The Correct Option is A

1. The sound pressure level in decibels is given by:
   \( L_p = 20 \log_{10} \left( \frac{P}{P_0} \right) \) 
2. Substituting \( L_p = 40 \, \text{dB}, \, P_0 = 2 \times 10^{-5} \, \text{Pa} \), we get \( P = 0.002 \, \text{Pa} \).