Pages in this set

Page 1

Preview of page 1
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…

Page 2

Preview of page 2
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
Kinetic…

Page 3

Preview of page 3
Amar Patel




1 kilowatts is equal to 1000 watts

Power (in watts) ­ rate of transfer of energy




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

Power = 10 000J = 400W
25s

The cost of Elctricity

Kilowatt-hours (kWh) are units of energy

A kilowatt-hour…

Page 4

Preview of page 4
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
steam
2. the steam makes a turbine spin
3. the spinning turbine turns a generator
which produces electricity
4. the…

Page 5

Preview of page 5
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…

Page 6

Preview of page 6
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
heat…

Page 7

Preview of page 7
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…

Page 8

Preview of page 8
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

Microwaves are used for satellite communication and heating food in…

Page 9

Preview of page 9
Amar Patel




security pens
fluorescent lights


X-rays

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
mutation…

Page 10

Preview of page 10
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…

Comments

Caitlin

Thank-you x

Similar Science resources:

See all Science resources »See all resources »