Consider a domestic hot water tank which has a total surface area of A = 2.7m². The tank and its contents are maintained at a constant temperature of 61C by an electric immersion heater and the temperature of the surroundings outside the tank is 20C. The emissivity of the tank is = 0.81.

Calculate the net power radiated by the tank (i.e. the difference between the power radiated and the power absorbed). Give your final answer to an appropriate number of significant figures.