Solve the Problem $\mathrm { D }$ Of a Sound Is Related to Its Intensity

question 289

Multiple Choice

Solve the problem.
-The decibel level $\mathrm { D }$ of a sound is related to its intensity $\mathrm { I }$ by $\mathrm { D } = 10 \log \left( \frac { \mathrm { I } } { \mathrm { I } _ { 0 } } \right)$ . If $\mathrm { I } _ { 0 }$ 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) \(2.44 \times 10 ^ { 15 }\) watt \(/ \mathrm { m } ^ { 2 }\)
• C) \(6.31 \times 10 ^ { - 4 }\) watt \(/ \mathrm { m } ^ { 2 }\)
• D) \(6.31 \times 10 ^ { - 5 }\) watt \(/ \mathrm { m } ^ { 2 }\)

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Definitions:

HBr

Stands for Hydrogen bromide, a compound that is often used in organic synthesis to convert alcohols into alkyl bromides.

Reagent

A material or mixture introduced into a system to initiate a chemical reaction or to check if a reaction takes place.

Transformation

A process of changing the chemical structure or physical form of a substance.

Organic Chemistry

The branch of chemistry concerned with the study of carbon-containing compounds, their reactions, and properties.