The Short Waves
We have learnt about the long waves of the spectrum, now we are going to look at the short waves. These have a shorter wavelength tan visible light. they carry more energy and are more dangerous.
Ultraviolet
Transfers more energy than visible light and is absorbed by most materials that absorb visible light.
The energy transferred can be used to disinfect water by killing microorganisms in it. Some materials absorb ultraviolet radiation and re-emit it as visible light. We call this fluorescence.. This is often used in security markings
Many low energy light bulbs are fluorescent lamps. A gas inside produces UV radiation when an electric current passes through it. A coating inside the glass then absorbs this and emits visible light.
X-rays
X-rays can pass through many materials that visible light cannot. They can pass through muscle and fat easily but bone will absorb more x-rays. This allows x-rays to be used to make images of inside the body .
Gamma Rays
Have the shortest wavelength and highest frequency of the electromagnetic waves, therefore transferring the most energy.
They can kill cells and are used to sterilise food and surgical equipment by killing any potentially harmful microorganisms.
Gamma rays are used to kill cancer cells in radiotherapy and can be used to detect cancer. A chemical that emits gamma rays is injected into the blood and will collect inside cancer cells. A scanner outside the body then locates the cancer by finding the source of gamma rays. Gamma rays can pass through all materials in the body.
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