3.7 kg of a fuel is completely burnt to give off 1.665 × 10^8 joules of energy. The calorific value of the fuel in standard unit is

Calorific value is defined as the amount of energy released per unit mass (kg) of fuel when completely burnt. The standard unit is J/kg or kJ/kg. Calorific value = Energy released / Mass of fuel = (1.665 × 10^8 J) / (3.7 kg) = 4.5 × 10^7 J/kg = 45000 kJ/kg = 45000 in standard kJ/kg units. Hence the calorific value is 45000 kJ/kg.