Key ideasKey ideas
The electromagnetic spectrum is made up of radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. They have different wavelength ranges.
12.3 Waves of the electromagnetic spectrum
Electromagnetic wave
Typical wavelength Source Detector Application
Radio waves
Microwaves
Infrared radiation
radio communication,
radio and TV broadcasting
10–1 m – 104 m
radio and TV
transmitterantenna
10–2 m microwave transmitter
microwave receiver
microwave oven, satellite
communication, radar
10–4 mWarm or
hot objects, the Sun
skin, phototransistor,
blackened thermometer
thermography, infrared viewer, infrared lamp, remote control, auto-focus ca
mera
Electromagnetic wave
Typical wavelength Source Detector Application
Visible light
Ultraviolet radiation
X-rays 10–10 m
10–8 m
10–7 mhot objects,
the Sun, fluorescent materials
very hot objects, the
Sun, mercury lamp
X-ray tube
human eyes, photographic
film
fluorescent materials
photographic film
illumination
production of vitamin D,
sterilization, checking
banknotesmedical
diagnosis, checking for
cracks in joints
Electromagnetic wave
Typical wavelength Source Detector Application
Gamma rays 10–12 m radioactive substances
photographic film, Geiger-
Muller counter
kill cancer cells, sterilize
food
