Which SI base quantity is measured in kelvin?

• A. Length
• B. Mass
• C. Temperature
• D. Electric current

Answer: (C)

Kelvin is the SI base unit used to measure temperature. The Kelvin scale is an absolute temperature scale, starting at absolute zero, which is the point where molecular motion ceases. This scale is particularly important in scientific contexts because it provides a direct relationship between thermal energy and temperature, facilitating calculations in thermodynamics and other fields of physics.

In contrast, the other options represent different physical quantities measured by other units: length is measured in meters, mass is measured in kilograms, and electric current is measured in amperes. Each of these quantities has its own distinct SI unit, underscoring the unique role that temperature plays in the broader context of physical measurements. Understanding that kelvin pertains specifically to temperature helps clarify its significance in physical and engineering applications.