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.