WAEC Physics 2012 Paper

Concept:Heat is a form of energy, so its S.I. unit is the same as that of energy.Explanation:Heat is the thermal energy transferred from one body to another due to a temperature difference.In the International System of Units, all forms of energy are measured in joule ($\mathrm{J}$).Kelvin ($\mathrm{K}$) is the S.I. unit of temperature, not heat.Watt ($\mathrm{W}$) is the S.I. unit of power.Ampere ($\mathrm{A}$) is the S.I. unit of electric current.Since heat is energy, its correct S.I. unit is the joule.Answer:The S.I. unit of heat is joule, i.e., Option A.