Chapter 15, Problem 46A

To determine

To calculate: The variation in sound pressure.

Answer to Problem 46A

The variation in sound pressure = $\underset{\_}{\text{2}\times {\text{10}}^{-2}\text{ Pa}}$ .

Explanation of Solution

Given:

Sound level of the conversation = $60\text{ dB}$

Calculation:

Pressure variation of a barely audible whisper = $2\times {10}^{-5}\text{ Pa}$

The sound level of a barely audible whisper = $0\text{ dB}$

Increase in sound level = $60\text{ dB}-0\text{ dB}=60\text{ dB}$

As sound pressure increases ten times for every $20\text{ dB}$ increase in sound level, therefore, the sound pressure will increase by $10\times 10\times 10=1000\text{ times}$ .

Pressure variation at $60\text{ dB}$ = $2\times {10}^{-5}\times \text{1000 = 2}\times {\text{10}}^{-2}\text{ Pa}$

Conclusion:

The variation in sound pressure = $\underset{\_}{\text{2}\times {\text{10}}^{-2}\text{ Pa}}$ .