CRITICAL RADIUS OF INSULATING MATERIAL

At particular radius of insulation over a cylinder. loss of heat is maximum.The unit consists of a G,l. pipe provided with plaster of Paris insulation on out side surface. Four pipes are provided with heater inside having input control, Input to heaters is measured by common voltmeter and ammeter, by controlling input to heaters, it is shown that critical radius of insulation is ratio of thermal conductivity and outside heat transfer co-efficient.