Module 4 Chapter 2 Electricity: Energy, Power and Resistance Flashcards
1
Q
Why do electrical bills use kilowatt-hours rather than joules?
A
Because the amount of energy used in a typical household is so great that it would be silly to use units as small a joules. A kilowatt-hour is 3,600,000 times larger than a joule.
2
Q
How do you calculate the cost of using a given amount of energy?
A
cost (£) = energy (J / kW h) * cost per unit of energy (£ J-1 / £ (kW h)-1)
