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Microwaves are a form of electromagnetic radiation. These waves are
similar to radio and television waves. They are in fact short
high-frequency electromagnetic waves, which range in length from one
millimeter to thirty centimeters.
Special electron tubes have been developed for the generation of
microwaves. This is because microwaves have been found to be useful
in many areas. The special electron tubes, which are used to
generate microwaves, are called klystrons and magnetrons. These
electron tubes have built-in devices that control the frequency of
microwave that is generated. Some of the areas where microwaves are
put to work for us include the very popular microwave ovens, radio
and television, radar, meteorology, satellites and certain types of
scientific research. |
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In a microwave oven, when microwaves come
into contact with food they agitate the water molecules present in
food. When this happens, heat is generated and food gets cooked.
Microwaves cannot pass through metal, but they can pass through
glass, ceramic and certain specially made cookware. Electricity is
used by the magnetron tube in a microwave oven to produce
microwaves. When microwaves are produced by the magnetron in the
oven, they enter the cooking cavity through openings meant for the
purpose. At the same time, stirrers scatter the waves evenly
throughout the oven. So all the food gets cooked evenly. Microwave
ovens are so designed that no microwaves pass through the walls of
the oven. Exposure to microwaves can prove very dangerous. Burns,
damages to the nervous system and cataracts have been found to be
among the detrimental effects of microwaves on human beings.
Television signals are sent and received through microwave relay
stations. Being shorter than normal television waves they can travel
farther. Many stations receive microwave signals and retransmit them
in the form of normal television signals. Telephone companies also
use microwaves when longer distances have to be covered and a large
amount of data has to be transmitted. Radar telescopes and
satellites use microwaves too. Microwaves are used for many
scientific studies like radar imagery, geologic mapping, etc.
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Application of
microwaves in telecommunication |
A major scientific application of
microwaves is called Maser. Maser is an acronym for microwave
amplification by stimulated emission of radiation. This is a device
that amplifies or generates microwaves or radio waves. A maser
producing radiation in the optical region is called a laser. We owe
the first maser oscillator to the American physicists Charles Hard
Townes, James P. Gordon, and Herbert J. Zeiger. Other noted
scientists involved in research using microwaves are Nikolay
Gennadiyevich Basov a Soviet physicist, Aleksandr Mikhailovich
Prokhorov also a Soviet physicist and an American physicist Charles
Hard Townes. The Nobel Prize in physics in 1964 for developing the
maser and the laser was shared by all three of them. |
