The first section is radio waves. These waves have the longest wavelength, and lowest frequency. They are used for satellite transmissions: communicating and broadcasting. Very large doses can cause cancers (such as leukaemia), and other disorders. Luckily, most people aren't ever in contact with large doses, so this isn't much of a cause for concern.
Microwaves have a slightly higher frequency and lower wavelength than radio waves, and are obviously used for cooking in microwave ovens (the energy causes particles to vibrate in food), but they are also used in satellite transmissions. These waves however, can cause damage to body tissues as it heats them up. This can cause enzymes to denature and irreparable tissue damage. Microwaves are contained, though. In microwave ovens, they are contained within the appliance and only emitted when sealed and on. People who work on aircraft carriers and are exposed to high doses of microwaves wear clothing that reflects the radiation.
Infrared radiation is used for short range communications, such as in tv remote controls, and also for heating (toasters, heat lamps, etc.) as well as night vision equipment and thermal imaging. All objects emit IR to some degree. Its only danger is overheating, which can be avoided by attempting to cool yourself down. Have a cold drink maybe?
Visible light is the light and colours detectable by our unaided vision. It is used in photography, optic cables, screens, printers, DVDs, and anything we need to see! Dangers are simply that too much light can damage the retina in the eye and cause temporary or permanent vision loss. This can be remedied by simply not looking at bright things, like the sun (our body's natural reflexes tend to help us avoid this anyway)
Ultraviolet, or U.V. light, is emitted by the sun. It's used for tanning beds, fluorescent lights, detecting forged bank notes, hardening dental fillings, reading invisible ink, and sterilising water and food. It has many dangers, however. For example, sun burn, skin cancer and vision damage or loss. By wearing U.V.-blocking sunglasses, sun cream, and covering up with hats, clothing and shade, the effects of U.V. can be reduced.
X-rays are useful for seeing inside things, such as the bones in your body, or looking in suitcases in airports without having to open and check through it. In seeing bones, x-rays are sent through the patient, and areas such as bones absorb the radiation, leaving a white patch, while the soft tissue is easily travelled through by the rays. X-rays can cause cell damage and cancer, so precautions people who work with them daily, such as doctors or airport security include standing behind a lead shield, or containing it within a lead box. Patients receiving an x-ray near to vital organs may have lead sheets placed over their heads or chests.
Gamma rays are able to kill living cells, so are used to target cancer cells and kill them. This is very precise and avoids damaging other cells or tissue. This is called radiotherapy. It is also used in radioactive tracers, which can be put inside a patient's body to see what part of it isn't working correctly. They are also used to sterilise food and medical equipment. However gamma rays can be very dangerous. They cause mutations, especially in rapidly growing tissue (in unborn babies this is especially dangerous). It can cause cell damage, and a variety of cancers. Gamma rays can be trapped by a few feet of lead, water or concrete. Thick, dense shielding is necessary for protection.
Useful resource: http://www.darvill.clara.net/emag/index.htm
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