# P1 Electrical Energy

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• Created by: KAustria
• Created on: 10-06-14 22:08
What are the common electrical appliances and what are their uses?
1. Lamps to produce light 2. Eelectric mixers to produce kinetic energy 3. Speakers to produce sound energy 4. Televisions to produce light and sound energy
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What useful energy transfer takes place in an electric drill?
Electrical energy kinetic energy
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Define power in an ppliance?
The rate in which an appliance transfers energy
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What is the unit of power?
Watt
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What is an alternative unit to watts?
kilowatts kW
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How many watts are there in a kilowatt
1000
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What is the equation given for power?
P(power in watts) = E (energy in joules) / t (time in seconds for energy transfer)
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How can you write the efficiency equation in terms of power?
Efficiency = useful power/ total power in x 100
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Why is the joules not a suitable unit to measure customer electrical use?
Because of the large amount of numbers involved.
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What is the amount of energy in the mains electricity measured in?
kilowatt-hour kWh
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What is kilowatt-hour?
The amount of energy transferred by a one-kilowatt appliance when used for an hour.
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What is the equation used to find the amount of energy transferred to a mains appliance?
E (energy in kWh) = P (power in kW) x t (time taken in hours)
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What does an electrical meter do?
Records the number of kWh of energy used.
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How can the amount of electrical energy used between the readings be calculated?
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what is equation used to calculate the cost of the electrical energy supplied?
Total Cost = number of kWh x cost per kWh
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What does cost effective mean?
Getting the best value for money
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What are things you must consider when figuring if something is cost effective?
1. The cost of buying the appliance 2. The cost of installing the appliance 4. The running costs 5. The maintenance cost 6. Environmental cost 6. interest charged on a loan.
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What is the payback time?
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

What useful energy transfer takes place in an electric drill?

#### Back

Electrical energy kinetic energy

### Card 3

#### Front

Define power in an ppliance?

### Card 4

#### Front

What is the unit of power?

### Card 5

#### Front

What is an alternative unit to watts?