Question
In an electric heater, the heat is continuously produced but its temperature becomes constant after some time. Why?
Solution
Heat is produced when current is passed in the electric heater. This increases the temperature of the coil.
Also, hot bodies radiate the heat and rate of loss of heat increases with the increase in temperature.
i.e.,
Thus, heat is produced in the heater coil by current.
At the same time it is radiating the heat by means of radiations.
At some temperature when the rate of heat produced in electric heater due to current is just equal to the rate of loss of heat by radiation, at that temperature equilibrium is set up and temperature becomes constant.
Also, hot bodies radiate the heat and rate of loss of heat increases with the increase in temperature.
i.e.,
Thus, heat is produced in the heater coil by current.
At the same time it is radiating the heat by means of radiations.
At some temperature when the rate of heat produced in electric heater due to current is just equal to the rate of loss of heat by radiation, at that temperature equilibrium is set up and temperature becomes constant.
