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Flashcards in P1 3 Electrical Energy Deck (15):
0

What are electric appliances designed for?

A particular purpose

1

What should electrical appliances do?

Waste as little energy as possible

2

What is power?

The rate of energy transfer

3

If an appliance is more powerful, what happens to the rate at which it transfers energy?

It becomes faster

4

What is electrical power measured in?

Watts / kilowatts

5

What is a watt?

The rate of energy transfer of 1J/s.

6

How many watts are in a kilowatt?

1000

7

What is power equal to?

Energy/time
Power is in watts, energy is in joules and time is in seconds

8

How is the efficiency of power calculated?

Useful power out/ total power in (x100%)

9

What does the energy supplied to a device depend on?

How long it is used for and the power supplied to it.

10

What is a KWh?

A unit of energy; energy supplied to an 1KW appliance in an hour.

11

What does the total cost equal to?

The number of KWh used x cost per KWh

12

What do electrical appliances do?

They transfer electrical energy into useful energy very quickly.

13

What does cost effectiveness mean?

Getting the best value for money.

14

In order to compare the cost effectiveness of different appliances, what do you need to consider?

Account of costs to buy it, running costs and other costs such as environmental costs.