2. If energy costs 8 cents per killowatt-hour, what will be the cost to run the heater in the previous problem at 220 V for a week?
3. It requires 3.35X105 J to heat 1 litre of water from
to the boiling point. If you heat the water in a 1000 W electric kettle which is 100% efficient:
(a) how long will it take to bring the water to the boiling point?
(b) at 8 cents per kW-hr, how much will it cost?
Return to Study Guide 8