Multiple choice Calorific value of a fuel is time needed for one kilogram of fuel to be burnt out completely change in state of the fuel time needed for half kilogram of fuel to be burnt out completely amount of heat energy produced on complete combustion of one kilogram of fuel heat energy needed to burn the fuel Reveal answer Fill a bubble to check yourself D Correct answer Explanation The amount of heat energy produced on complete combustion of one kilogram of fuel is called its calorific value.