# Physics

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What do electrical appliances do?
Electrical appliances transfer electrical energy into whatever form of energy we need at the flick of a switch.
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An electrical appliance is designed for a particular purpose and should what?
It should waste as little energy as possible.
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Name some common electrical appliances.
Lamps, to produce light. Electric mixers, to produce kinetic energy. Speakers, to produce sound energy. Televisions, to produce light and sound energy.
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What is power?
The power of an appliance is the rate at which it transfers energy.
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What is the equation for finding power?
P = E divided by t. Where P is the power in watts, W. E is the energy in joules, J. And where t is the time taken (in seconds) for the energy to be transferred.
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Often a watt is too small a unit to be useful, so power may be given in what?
It may be given in kilowatts (kW). 1 kilowatt = 1000 watts.
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What is a kilowatt-hour?
A kilowatt-hour is the amount of energy transferred by a one-kilowatt appliance when used for one hour.
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The amount of energy transferred to a mains appliance can be found using what equation?
E = P x t. Where E is the energy transferred in kilowatt-hours, kWh. P is the power of the appliance in kW. t is the time taken (in hours) for the energy to be transferred.
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A kilowatt-hour is a unit of what?
Energy.
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Cost effectiveness is what?
Cost effectiveness means getting the best value for your moneyW
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What is the payback time for an appliance?
The payback time is the time it takes for an appliance or installation to pay for itself in terms of energy savings.
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## Other cards in this set

### Card 2

#### Front

An electrical appliance is designed for a particular purpose and should what?

#### Back

It should waste as little energy as possible.

### Card 3

#### Front

Name some common electrical appliances.

What is power?

### Card 5

#### Front

What is the equation for finding power?