Kamis, 31 Maret 2011

article active and passive voice

Electronics


Electronics plays a part in almost everyone life.radio and television sets are electronics devices .so are tape recorders and video or movie cameras and their projectors.doctors and dentist use x-ray machines,one of the first electronic inventions.in a long distance phone call,your voice is relayed over a great distance by other electronic devices.
Electronics is also important in industry,large x-ray machines are used to ‘see’ trought as much 10 to 20 inches of solid metal,in this way engineers can detect weaknesses inside such things as welded pipes ,airplane wings ,and railroad-car wheels.another electronic device counts cant oving alon a belt in a canning factory.if a dented can comes along,an electronically controlled steel bar pushes the dented can off the belt.
Electronic instrument are important in scientific research.atomic physicists work with giant electronic machines called particle accelerators.these accelerators are also called atom smashers.scientists turn to electronic computers to do huge amount calculating.electronic miscroscopes magnify very small things far beyond the power of any kind of microscope.
Radar ia another valuable electronic invention.it guides airplanes into crowded airpots,even when the ground is covered by fog.it enables pilots to locate and fly around storm high above the earth.missiles,earth orbiting satellites,and space probes are tracked by means or radar

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