HEAT HEAT Heat is a form of energy and is defined as: "The total kinetic energy of all the molecules of a body " SYMBOL It is denoted by "Q" or "q" UNITS (1) Joule (2) B.T.U (3) Calorie CONVERSION 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. THERMOMETRIC PROPERTIES 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 THERMAL EQUILIBRIUM 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. TEMPERATURE "Average kinetic energy of the molecules of a body is called temperature." Temperature describes the degree of hotness of a body.