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AQA Physics PHY1

Heat Transfers

Conduction ­
In solids
Energy of molecules stored as vibrations
Molecules bonded together so kinetic energy passes along

Metals are the best conductors as they have free electrons, which can move
around passing the energy along quicker.

Convection ­
Liquids and gases…

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AQA Physics PHY1

4. Double-glazed windows ­ dry air in between is an insulator. Stops
convection and conduction

5. Draught proofing ­ foam around doors and windows
Stops convection

6. (Thick curtains ­ reduces heat loss through conduction and radiation)

Small objects have a large S.A:…

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AQA Physics PHY1

Energy Efficiency

Conservation of energy- Energy is never made or destroyed. It only changes
from one form to another.

Most energy transfers involve some losses often has heat.
The less energy lost the more efficient a device is.

No device is 100% efficient
Wasted energy is often…

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Electrical Distribution

Nation grid = network of pylons and cables
It takes it from power stations to the places in need

You need a high current or a high voltage

High Current = loss of energy due to heat
Cheaper to have a higher voltage (400,000 V)…

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AQA Physics PHY1

1. All 3 release carbon dioxide. Coal releases the most then oil and gas. All
this adds to the green house effect and contributes to climate change.
2. Coal release sulfur dioxide causing acid rain.
This is reduced by taking the sulfur out before its' burnt.

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AQA Physics PHY1

6. No power when wind stops. No means of increasing the supply.
7. Initial costs are high but no fuel costs and minimal running costs.

1. Solar cells create electricity directly from sunlight. Initial expensive. Ideal
for appliances not requiring much energy.
2. Remote places

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Comparison of Energy resources
Coal and oil are running out but gas is not so power stations turning to gas
ones as they are quickest to set up.

Set up costs ­ Renewable need bigger station which are more expensive.
Set up time - affected by size,…

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AQA Physics PHY1

Security Marker pens, anti theft dusk.

Gamma Ray X-Ray UV Visible Infrared Micro Wave Radio

All the different types of waves travel at the same speed in a vacuum.
EM waves can be absorbed, transmitted or reflected.
They react differently in different matters.
When it is absorbed…

Page 9

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AQA Physics PHY1

These ions react easily with chemicals in our cells damaging our genes leading
to cancer.
A cell's genetic instructions go wrong.

X-rays - Firing a beam of electrons at a metal target makes X-rays.
As the electrons slow down in the target they give off kinetic energy…


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