1. Ze Electromagnetic Spectrum
By Will B

2. Electromagnetic waves
The different waves that make up the electromagnetic spectrum are as follows in order of increasing frequency;
Radio -> Microwave -> Infrared -> Light -> Ultraviolet -> X-ray -> Gamma.
All these waves can travel through a vacuum.
They are also all transverse waves.

3. Radio Waves Has a frequency of 103 – 1012 Hertz
Has a wavelength of 105 – 10-4
Radio waves will be reflected and refracted by the ionosphere as it is electrically charged.
Radio waves main uses are radio and television broadcasts.
Radio waves can produce a chosen
frequency, so they won’t interfere with
other radio waves.
This allows for more than one radio
station to broadcast in an area.

4. Microwaves Have a frequency of 103 to 1012 hertz
Have a wavelength of 105 to 10-4 metres
Microwaves are not reflected by the ionosphere and so are used for communications with satellites.
Microwaves have shorter wavelengths, this makes them ideal for handheld communication devices such as mobile phones.

5. Infrared Has a frequency of 1011 to 1013 hertz
Has a wavelength of 10-3 to 10-5
They use total internal reflection to be carried along optical fibres.
They are responsible for heat radiation, when you feel warmth from a bonfire, it is because infrared waves carry the heat.
Infrared waves are also used in toasters and grills to cook food.

6. Visible light
Human eyes can detect electromagnetic wavelengths from about 400nm (violet) to 700nm (red).
Visible light can be totally internally reflected within glass.
This allows images to be transported directly from one place to another.

7. Ultraviolet Has a frequency ranging from 7.5 x 1014 to 3 x 1016 hertz.
Has a wavelength 10-6 to 10-9
Some ultraviolet waves are used in the treatment of sewage to kill bacteria.
To much exposure to ultraviolet waves can cause sunburn in humans.

8. X-rays Has a frequency of 1015 to 1020
Has a wavelength of 10-7 to 10-12
Very high energy electromagnetic waves can be produced by colliding high speed electrons with a metal target. When these electrons decelerate rapidly, they give off energy as x-rays.

9. Gamma Has a frequency of 1017 to 1024
Has a wavelength of 10-9 to 10-16
Generated by energy shifts inside the nuclei of atoms, gamma rays form the very highest energy EM waves.
Used to sterilise surgical instruments
Gamma rays can be used to kill cancerous cells in the body.