All the waves in the electromagnetic spectrum...

• travel the same speed in a vacuum;
• can be reflected, refracted, diffracted and polarised;
• are transverse waves.

It is important that you are able to rememeber the different parts of the electromagnetic spectrum and their properties.

A list of the spectrum is shown below:

Type of ray:	Gamma rays:	X-rays:	Ultraviolet:	Visible light:
Production:	Emitted during radioactive decay	Produced by firing electrons at a metal target	Emitted by the Sun	Emitted by the Sun
Uses:	Medicine in chemotherapy	Medicine for looking at bones	Tanning	Seeing
Hazards:	Causes cancer by damaging cells	Causes cancer by damaging cells	Can cause skin cancer	Intense light can damage your sight
Wavelength (m):	x10-12	x10-10	x10-8	7 x10-7 to 4x10-7
Frequency (Hz):	x1020	x1018	x1015	x1014
Photon Energies (eV):	400 k	4 k	4	0.4

Type of ray:	Infra red:	Micro-waves:	Radio-waves:
Production:	Emitted by hot objects	Produced by changing currents in a conductor	Produced by changing currents in a conductor
Uses:	Conventional cooking	Microwave cooking and communications	Communication and media
Hazards:	Can burn	Can burn	Currently not considered to be hazardous
Wavelength (m):	x10-5	x10-3 to x10-2	x 1
Frequency (Hz):	x1012	x1010	x108 to x1010
Photon Energies (eV):	4µ	40µ	4

All of the waves in the electromagnetic spectrum are oscillating electric and magnetic fields. These fields are perpendicular to each other.

These waves can be produced by oscillating electrons in a conductor which sets up the alternating fields. Likewise, the waves can be detected, as the fields will cause electrons to oscillate in a conductor. This is the basic principle behind the production and transmission of radio waves.

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