Rate at which energy is received by a square meter of area facing the sun is
1400 Wm-2. Assume 50% efficiency for conversion of this energy in to heat and find
the amount of time it takes for the temperature of 10 kg of water to rise through
10 C0
due to energy received by a 2m ? 2m area. Assume the surface always faces
the sun. How many kilowatt-hours of energy is this equal to? How long would a 40 W lamp glow if thisenergy were converted in to electrical energy at 25 %effiency