Celsius Celsius The Celsius scale, also known as the centigrade scale, is a temperature scale used by the International System of Units (SI). As an SI derived unit, it is used by all countries except the United States, the Bahamas, Belize, the Cayman Islands and Liberia. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference between two temperatures or an uncertainty. Before being renamed to honor Anders Celsius in 1948, the unit was
Temperature which implies Since the first function is independent of "T", this temperature must cancel on the right side, meaning "f"("T","T") is of the form "g"("T")/"g"("T") (i.e. "f"("T","T") = "f"("T","T")"f"("T","T") = "g"("T")/"g"("T")· "g"("T")/"g"("T") = "g"("T")/"g"("T")), where "g" is a function of a single temperature. A temperature scale can now be chosen with the property that Substituting (4) back into (2) gives a relationship for the efficiency in terms of temperature: For "T" = 0 K the efficiency is 100% and that efficiency becomes greater than 100% below 0 K. Since an efficiency greater than 100% violates the first law of thermodynamics,