Relative Intensity Level

Formulas Used

Other Skills

• Calculations with scientific notation

1. As a jogger hears the bark of an approaching dog, the sound reaching her ears has an intensity of 4.19 × 10^-7 W/m². What is the relative intensity level of the barking?
2. A student walking past the alarm during a fire drill perceived the relative intensity level of the alarm to be 82.4 dB. What was the intensity of the sound he heard?
3. When one flutist plays a note, the conductor hears the note at a relative intensity level of 42.0 dB. What relative intensity level would the conductor perceive if 6 additional flutists started playing at the same volume? (You may assume that all flutists are equidistant from the conductor, and that the first flutist is still playing.)
4. A girl stands 4.1 m from a radio whose sound output is 9.17 × 10^-6 W. What is the relative intensity level of the sound she hears?
5. What sound power would be required for a listener 11 m away to perceive a siren’s relative intensity level to be 75 dB?
6. A would-be burglar trips an alarm that emits 1.77 × 10^-4 W of sound power. How far away will the burglar have to run before the relative intensity level of the alarm will dwindle to 65 dB?