What is a decibel used for?

A decibel is a logarithmic unit used to measure the relative loudness of a sound. It quantifies sound intensity in relation to a reference level. In sound measurement, the decibel scale enables one to express large variations in sound pressure levels in a more manageable format; for example, a small increase in sound may translate into a noticeable change in perceived loudness. This measurement is crucial in environments where noise control is essential, such as in refrigeration systems and HVAC applications, to ensure compliance with noise regulations and to protect the health and comfort of individuals in the vicinity.

The other choices do not accurately define a decibel. Temperature is measured in degrees (Celsius, Fahrenheit, Kelvin), electrical resistance is measured in ohms, and pressure is typically measured in pascals, bar, or psi. Each of these concepts is distinct and serves specific functions within the field of physics and engineering.