Q.Distinguish between heat and temperature.

Heat and Temperature

In everyday speech "heat" and "temperature" are used interchangeably, but in physics they are entirely different quantities — confusing them causes many errors in thermodynamics.

Temperature

Temperature is the degree of hotness or coldness of a body — a measure of the average kinetic energy of its molecules. It is a scalar, measured with a thermometer, in kelvin (K) in SI (also °C, °F). Temperature decides the direction of heat flow: energy always flows spontaneously from a body at higher temperature to one at lower temperature, regardless of their sizes.

Heat

Heat is energy in transit — energy that flows from one body to another because of a temperature difference. It is a form of energy, so its SI unit is the joule (J) (the older unit is the calorie, $1\ \text{cal} = 4.186\ \text{J}$). A body does not "contain heat"; it contains internal energy. Heat is the name for that energy while it is being transferred.

The crucial distinction

• A cup of warm water and a bucket of slightly-warm water can carry the same total heat energy even though the cup is at a higher temperature — temperature is intensive (independent of amount), heat depends on how much substance there is. …