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|
|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.