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Amar Patel

Physics- Energy and Electricity
Heat energy is transferred from high to low temperature. Heat transfer takes place in
three ways:

1) Radiation is energy carried by electromagnetic waves
The sun gives out radiation in all parts of EM waves. Fortunately for us, the Earth's
atmosphere blocks most of…

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Amar Patel

Energy Transfer
Energy exists in different forms
Energy can change from one form into another form
Energy cannot be created or destroyed

Nine types of Energy

Electrical Energy- whenever a current flows
Light energy- From the Sun, light bulbs, etc.
Sound energy- energy released by vibrating objects

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Amar Patel

1 kilowatts is equal to 1000 watts

Power (in watts) ­ rate of transfer of energy

A motor transfer 10000J of energy in 25s. What is its power?

Power = 10 000J = 400W

The cost of Elctricity

Kilowatt-hours (kWh) are units of energy

A kilowatt-hour…

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Amar Patel

The National Grid

The National Grid is a network of cables and transformers.

There are four main stages:
1. the fuel is burned to boil water to make
2. the steam makes a turbine spin
3. the spinning turbine turns a generator
which produces electricity
4. the…

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Amar Patel

energy transfer diagram for the generation of electricity from a fossil fuel such as coal.

Disadvantages of using fossil fuels
Fossil fuels are non-renewable energy resources. Their supply is limited and they will
eventually run out. Fossil fuels do not renew themselves, while fuels such as wood can…

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Amar Patel

A wave generator is a floating
generator turning by the waves

Hydroelectricity generators are turned
by water running downhill

A tidal power station traps each high
tide and uses it to turn generators

We can convert solar energy into
electricity using solar cells or use it to

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Amar Patel

Wavelength is the distance
from one peak to the next.
Frequency is how many
complete waves. It's
measured in hertz. (1 Hz is 1
wave length). All
electromagnetic waves travel
through space at a speed of
300 million m/s. All the
different types of
electromagnetic wave travel at…

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Amar Patel

Short-wave radio signals (TV and FM radio) can, like long waves, be received at long distance
from the Transmitter. That's because they are reflected from the ionosphere ­ an
electrically charged layer in the Earth's upper atmosphere.


Microwaves are used for satellite communication and heating food in…

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Amar Patel

security pens
fluorescent lights


X-rays mostly pass through skin and soft tissue, but they do not easily pass through bone
or metal. Radiographers in hospitals take X-rays photographs to help doctors diagnose
broken bones, X-rays can cause mutation which lead to cancer. Low doses cause cell

Page 10

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Amar Patel

Isotopes are atoms with different numbers of neutrons. E.g. The carbon-14 has two
more neutrons that `normal' carbon -12
Usually element only has one or two stable isotopes ­ like carbon -12. The other isotopes
tend to be radioactive- the nucleus is unstable, so it decays and emits…




Thank-you x

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