The body radiates energy or cools down to surrounding depends on the temperature of the surrounding. It says that the rate of heat loss to the surrounding at higher temperature is more than that of the body at lower temperature.

To perform that we take a metal ball of mass 1 kg is heated by means of a 20 W heater in a room at 20ºC. The temperature of the ball rises continuously but the rate of increase in temperature decreases continuously and finally it becomes zero, when the temperature of the ball reaches to 50ºC. Corresponding to above observation answer the following questions.

(i) Find the rate of loss of heat to the surrounding when the ball is at 50ºC.