The Decibel (DB) Is Defined As $\mathrm { dB } = 10 \log \frac { P _ { 2 } } { P _ { 1 } }$

Multiple Choice

The decibel (dB) is defined as $\mathrm { dB } = 10 \log \frac { P _ { 2 } } { P _ { 1 } }$ , where P2 is the power of a particular signal and P1 is the power of some reference signal. In the case of sounds, the reference signal is a sound level that is just barely audible. How many dBs does a sound have if its power is 7,320,000 times that of the reference sound? Round to the nearest tenth.

A) 158.1 dB
B) 68.6 dB
C) 29.8 dB
D) 10.0 dB
E) 0.0 dB