Absolute zero is the lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reaches its minimum value, taken as 0. The theoretical temperature scales set their zero points at absolute zero by definition.temperature is determined by extrapolating the ideal gas law; by international agreement, absolute zero is taken as -273.15° on the Celsius scale (International System of Units), which equates to -459.67° on the Fahrenheit scale (United States customary units or Imperial units).

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