Concept:Heat is a form of energy. Its SI unit is the same as the SI unit of energy, which is the joule.
Explanation:In the International System (SI), energy is measured in joules. One joule equals the work done by a force of one newton over a distance of one meter.
Heat is simply energy transferred due to temperature difference, so it uses the same unit.
Other common units for heat are not SI units.
The calorie is defined as the heat needed to raise 1 g of water by 1°C, but it is not an SI unit.
Erg is the CGS unit of energy, equal to
10−7 joules.
Watt is the SI unit of power, not energy or heat.
Thus, among the given options, the correct SI unit of heat is the joule.
Answer:A. joule