00 K or absolute zero is the lowest temperature on the Kelvin temperature scale and considered as the lowest temperature possible. This is the reason that all temperatures on the Kelvin scale are in positive figures.
It was finding of J Charles that volume of a gas at -273.15°C will be zero or gas will not exist at this temperature. This temperature is called absolute zero.
This scale is also called a thermodynamic scale of temperature, and degree sign is not used in this scale.
To convert Celsius temperature into Kelvin, we add 273.15 to Celsius temperature.
