Which of the following statement correctly explain calorific value of a fuel?

The amount of heat energy produced on complete combustion of 1 kg of a fuel.

The correct answer is option 3. The amount of heat energy produced on complete combustion of 1 kg of a fuel.

The calorific value of a fuel is a measure of the amount of heat energy produced when a specified quantity of the fuel undergoes complete combustion. It is typically expressed in terms of energy per unit mass, and the standard unit used is kilojoules per kilogram (kJ/kg) or megajoules per kilogram (MJ/kg).

So, the correct statement, "The amount of heat energy produced on complete combustion of 1 kg of a fuel," means that the calorific value is calculated for a mass of 1 kilogram of the fuel. This standardization allows for easy comparison of the energy content of different fuels on an equal basis.

For example, if a fuel has a calorific value of 30 MJ/kg, it means that 1 kilogram of that fuel, when completely burned in a combustion process, releases 30 megajoules of energy. This information is crucial for various applications, including energy production, as it helps in determining the efficiency and potential energy yield of a particular fuel source.

In contrast, if the statement were "The amount of heat energy produced on complete combustion of 100 kg of a fuel," it would mean the calorific value is expressed for a much larger quantity (100 kilograms), making direct comparisons with other fuels less straightforward. The standardization with respect to 1 kilogram allows for a more consistent and universally applicable measure of a fuel's energy content.