What is the value of absolute zero in Kelvin?

The value of absolute zero in Kelvin is defined as 0 Kelvin. Absolute zero represents the theoretical lowest temperature possible, where all molecular motion ceases. In the Kelvin scale, which is used primarily in scientific contexts, this fundamental point of temperature is established as 0 K.

The Kelvin scale is an absolute temperature scale that starts at absolute zero, with each increment corresponding to an equivalent increase in thermal energy. This means that temperatures in Kelvin do not have negative values, which distinguishes it from Celsius or Fahrenheit scales where zero can be below absolute zero. Thus, 0 Kelvin signifies the absence of thermal energy, making it the correct and fundamental value for absolute zero.

Understanding that other temperature scales like Celsius would have a conversion—a Celsius temperature of -273.15 corresponds to 0 Kelvin—clarifies why only 0 K accurately represents absolute zero in the Kelvin system.