The Decibel Level $D$ Of a Sound Is Related to Its Intensity

Multiple Choice

The decibel level $D$ of a sound is related to its intensity $I$ by $D=10 \log \left(\frac{I}{I_{O}}\right)$ . If $I_{O}$ is $10^{-12}$ , then what is the intensity of a noise measured at 78 decibels? Express your answer in scientific notation, rounding to three significant digits, if necessary.

A) $7.8 \times 10^{-10} \mathrm{watt} / \mathrm{m}^{2}$
B) $2.44 \times 10^{15} \mathrm{watt} / \mathrm{m}^{2}$
C) $6.31 \times 10^{-5} \mathrm{watt} / \mathrm{m}^{2}$
D) $6.31 \times 10^{-4} \mathrm{watt} / \mathrm{m}^{2}$