Relative measurement of intensity on a logarithmic scale is expressed in which unit?

• A. Newtons per cm squared
• B. Watts per cm squared
• C. Decibels
• D. Pascals

Answer: (C)

Decibels are used to express ratios on a logarithmic scale, making them ideal for relative measurements of intensity. When comparing a sound’s intensity to a reference level, we compute something like 10 times the log base 10 of the ratio (I/I0), and the result is given in decibels. This logarithmic scale compresses the vast range of real-world intensities into manageable numbers and aligns with how we perceive loudness in a roughly logarithmic way. The other options are physical units for absolute quantities—pressure (newtons per square centimeter or pascals) or power density (watts per square centimeter)—and do not inherently represent a relative, log-scale measurement.