# A 1,200-watt heater is used for raising the temperature of 1 liter of water to boiling point. How long will it take for the water to boil if the initial temperature of water is 20 C? (1 cal = 4.19 joules?)

Mar 29, 2017

1000g * 4.184 (J/g’C) * (100-20)’C = 334720 J
The heater supplies 1200 J/s, so the time to provide this heat to the water is $334720 \frac{J}{1200 \left(\frac{J}{s}\right)} = 278.9 s$ or 4.65 minutes.