# Physics OCR, P3

• Created by: SivaPriya
• Created on: 28-12-16 13:01
What issues does the demand for energy cause?
The Availability of energy sources and the environmental effects of using these sources
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What are the main primary sources of energy?
Fossil Fuels, Biofuels, Wind, Waves and Radiation from the Sun
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Why is electricity a secondary energy source?
It is generated form another energy source
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Why are power stations that burn fossil fuels bad?
What happens when an electric current passes
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What happens when an electric current passes through a component?
Energy is transferred from the power supply to the component and/or the environment
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What is power (Watts,W)?
A Measure of the amount of energy it transfers each second
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What is the equation for amount of energy transferred?
Energy Transferred= Power x Time (E=P x T)
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What is the equation to calculate the rate at which an eletrical device transfers energy?
Power= Voltage X Current (P= V x I)
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What is the equation for percentage of efficiency?
% Efficiency = (Usefully Transferred energy/ Total Energy Supplied) x100
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Why is electicity convenient?
It is easily transmitted over distances and can be used in many ways
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What is mains electricity produced by?
Generators
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How do generators produce a voltage?
Across a coil of wire by spinning a magnet near it
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What happens the bigger the current supplied by a generator?
The more Primary Fuel it uses every second
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How do Power Stations Work?
Heat boils water and produces steam, which drives the turbines and power the generators. Electricity produced sent to set-up transformer and the national grid. High voltages reduced by step-down transformer and then to our homes.
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Why is eletrcity distributed at high voltages?
To reduce energy losses
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What are disadvantages of nuclear power
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What is contamination?
If any part of a radiation source got on your clothes or entered your body. This would continually expose you to dangerous ionising radiation and therefore is a greater threat to your health than irradiation
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What does increased exposure to ionsing radiation cause?
Damage to living cells, eventually leading to cancer or cell death
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What is the main supply voltage to our homes?
230 Volts//240V
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What does the choice of energy source depend on?
Environmental impact, econmics, waste produced and carbon dioxide emissions
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What are advantages of fossil fuels?
High energy output, easily distributed and efficent
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What are disadvantages of fossil fuels?
Buring generates greenhouse gases, non-renewable and products damage the environment
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What are advantages of nuclear power?
Reliable, no greenhouse gases and high energy output
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What are disadvantages of nuclear power?
Disposal of nuclear waste is difficult, expensive, damage to environment
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Renewable and inexhaustible supply
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Needs a larger area of land to produce, burning leads to greenhouse gases and expensive to produce
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What are advantages of renewable energy?
Renewable, no greenhouse gases and no solid or liquid waste
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What are disadvantages of renewable energy?
Expensive, limited locations and not as reliable
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What do we need to ensure a security of electricity supply nationally?
A mix of energy source
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## Other cards in this set

### Card 2

#### Front

What are the main primary sources of energy?

#### Back

Fossil Fuels, Biofuels, Wind, Waves and Radiation from the Sun

### Card 3

#### Front

Why is electricity a secondary energy source?

### Card 4

#### Front

Why are power stations that burn fossil fuels bad?

### Card 5

#### Front

What happens when an electric current passes through a component?