The kiloton, which is used to measure the energy released in an atomic explosion, is equal to 4.2 × 1012 J (approximately the energy released in the explosion of 1000 tons of TNT). Recalling that 1 kilocalorie of energy raises the temperature of 1 kg of water by 1°C and that 4184 joules is equal to 1 kilocalorie, show that 4.0 × 108 kilograms of water (nearly half a million tons) can be heated through 50°C by a 20-kiloton atomic bomb.