P1 3 Electrical Power + Energy Flashcards Preview

AQA GCSE Science > P1 3 Electrical Power + Energy > Flashcards

Flashcards in P1 3 Electrical Power + Energy Deck (13):
0

Why should an electrical appliance waste as little energy as possible?

An electrical appliance is designed for a particular purpose so a small amount of energy should be wasted.

1

What are some uses of electrical appliances?

Electrical appliance uses can include: heating, lighting, making objects move by using an electric motor and creating sound and visual images.

2

What is power?

Power is the rate of transfer of energy.

3

Complete:

The more powerful an appliance ...

... The faster the rate at which it transfers energy.

4

What is the formula for calculating power?

Power = Energy / Time.

Power in watts W.
Energy in joules J.
Time in seconds s.

5

What is the efficiency of a device?

The efficiency of a device is the useful power out /
The total power in.

x 100 for a percentage.

6

What is a kilowatt-hour?

The energy supplied to 1 kW appliance in 1 hour.

7

What does the energy supplied to an appliance depend on?

• How long it's used for.
• The power supplied to it.

8

How to work out the total cost:

Total cost = number of kWh x cost per kWh.

9

What is a kilowatt-hour?

A unit of energy.

10

What does cost effectiveness mean?

Cost effectiveness means getting the best value for money.

11

What are all the costs of an appliance?

• Capital costs- buying and installing the equipment.
• Running costs- fuel and maintenance.
• Environmental costs- removal of old equipment and carbon tax.
• Other costs such as loan interests.

12

What is the payback time?

The payback time is the time taken for something to produce savings to match how much it cost.