Energy is the capacity to do work. Work includes heating things up, making things speed up or lifting things.
Energy is measured in Joules
Power is measures in watts
One watt for one second is the same as one joule. This is quite a small amount.
Energy = Power x Time = Voltage x Current x Time
Power = Voltage x Current
Energy supplied to homes or industry is measured in kilowatt hours.
One kilowatt hour costs 10 to 20p.
The cost depends on the price of oil, coal, gas and also seasonal or hourly demand levels.
With increasing renewable sources, the price also depends on available wind and sun light levels.
Generating stations measure power in megawatts or gigawatts.
Non engineers frequently confuse energy and power.
Last Name Class ID
Q: qNum of last_q
Q ID: Question ID
Score: num correct/num attempts
- You can attempt a question as many times as you like.
- If you are logged in, your first attempt, each day, is logged.
- To improve your scores, come back on future days, log in and re-do the questions that caused you problems.
- If you are logged in, your most recent wrong answers get remembered. This might help you and your teacher to correct your understanding.
- In the grade book, you can delete your answers for a topic before re-doing the questions. Avoid deleting unless you intend re-doing the questions very soon.