Computer and the Computing Environment

            Working with computers is not a hazardous business if you pay attention to your posture and take regular breaks from the keyboard. However, computers generate electromagnetic fields, which are know to affect the normal function of living cells. We don’t know-weather these emissions have any effect on human tissues, or what the consequences of exposure are, if there are any at all, but many scientist argue about this. And where there is an argument, there might be a reason.

What is Electromagnetism?

           

Electromagnetism is a form of one of the fundamental forces of the universe: electromagnetic radiation. In its natural state, electromagnetism comprises both magnetic fields and electrical charge, which combine to form electromagnetic waves. The two types of fields-electrical and magnetic-are related and arise from the same phenomena, but they have individual distinguishing characteristics:

·                     Electric fields generate a potential (a voltage), are measured in mill volts or volts per meter, and are relatively easy to shield against by using conductive materials.

·                     Magnetic fields generate a current (amperage). These fields are measured in milliamps per meter or sometimes in related units of gauss, and are difficult to shield against.

Electromagnetic waves are generated every time electricity or magnetism changes direction or strength. Since electricity is just the movement of electrons, and electrons are part of every atom that surrounds us, we are constantly bathed in a low level of EM radiation. Natural varieties include light, infrared and ultraviolet, cosmic rays from distend exploding stars and radio and radio signals from thunderstorm. Most modern technology relies on or produces electromagnetic radiation-radio, TV, microwave and X-ray are all examples. Electromagnetic radiation constantly varies in strength from zero to the maximum level of a particular signal and back again. The speed at which it does this defines the frequency, and thus the effects, of the radiation. A frequency of zero means the field is not moving at all-this is called an electrostatic field, in other words, a field where the electrons are static. Just above zero are the slowest forms of genuine electromagnetic radiation, called extremely low frequency (ELF) and very low frequency (VLF) radiation respectively. These have a repetition rate of between a couple and a few thousand times a second. Electrical appliances, house wiring, TVs and monitors radiate most at ELF and VLF. Above that in the radio spectrum are LF, MF and HF, for low, medium and high frequency. These are used almost exclusively as radio communication bands, and so most computers are shielded at these frequencies to prevent radiation and interference. The same is true of VHF and UHF-very and ultra high frequency-which are used for TV and stereo radio, walkie-talkies, mobile phones and the like. Above UHF is microwave radiation, then comes infrared, visible light, ultraviolet, X-rays and gamma rays. Although computers radiate some power at all of these frequencies, the health effects are well know and the levels of radiation are kept very low, where appropriate.