Heat is a form of energy and is defined as: “The total kinetic energy of all the molecules of a body “
It is denoted by “Q” or “q”
(1) Joule (2) B.T.U (3) Calorie
1 B.T.U = 251.996 Cal ( or 252 Cal) 1 calorie = 4.186 Joule ( or 4.2 joule)
FLOW OF HEAT
Natural flow of heat always takes place from a region of high temperature to a region of lower temperature.
Properties of a substance that vary uniformly with the variation in temperature are referred to as Thermometric properties. EXAMPLES: Volume , Density ,Viscosity , Pressure , Surface Tension , Area
When two bodies at different temperatures are brought into thermal contact , heat flows from hot body to cold body till the temperature of both the bodies becomes equal . This state is referred to as THERMAL EQUILIBRIUM.
“Average kinetic energy of the molecules of a body is called temperature.”Temperature describes the degree of hotness of a body.