Heat 3 Caltec S.6

PHYSICS HEAT This is the form of energy which gives a sensation of hotness or coldness of an object. Heat transfer from one place to another can only occur by Conduction Convection Radiation.. Temperature is the measure of the average kinetic energy of the molecules. ORIt is the degree of hotness or coldness of an object and it is measure in degrees. The instrument used for measuring temperature is athermometer. The SI unit of temperature is kelvin (K). Thermometers always use a measurable property of a substance which is sensitive to temperature changes. A thermometric property is a measurable property of a substance which varies linearly with temperature, can be measured accurately and remains constant at that temperature. The thermodynamic temperature scale This is the fundamental temperature scale adopted for scientific measurement. Thermodynamic temperature is denoted by (T) and is measured in kelvins. Celsius scale of temperature (θ)=T – 273.16K How to establish a Celsius temperature scale Requirements for setting up a temperature scale. Choose a physical property of a substance () Determine the value of the property at the upper fixed point of the thermometer () Determine the value of the property at the lower fixed point of the thermometer () The value of the property at the required temperature θ is also determined as () The temperature θ can be obtained from the expression Requirements A physical property of the substance which is sensitive to temperature changes and is constant at constant temperature. Fixed points. On a thermodynamic temperature scale, lower fixed point (ice point) is the temperature at which pure ice is in thermo equilibrium with pure saturated water vapor at standard atmospheric pressure. Its value is 273.16K. The upper fixed point (steam point) is the temperature at which pure boiling water is in thermo equilibrium withsteam …