Name the unit in which the calorific value of a fuel is expressed.

The unit used to express the calorific value of a fuel is “joules per kilogram” (J/kg) or “kilojoules per kilogram” (kJ/kg) in the International System of Units (SI). Alternatively, in specific systems of measurement, it might be indicated in “calories per gram” (cal/g) or “kilocalories per gram” (kcal/g).