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Electromagnetic Waves (There are 7 components (Visible light, Ultraviolet,…
Electromagnetic Waves
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uses of radio waves
Radio telescopes study the radio frequency portion of the electromagnetic spectrum emitted by astronomical objects, such as stars.
Radio waves produced by oscillating electric currents in a transmitting antenna is picked by radio and TV aerials at the receiving end.
uses of microwaves
Microwaves of a particular wavelength are readily absorbed by water molecules. Almost all food contains water, so food can be heated quickly in a microwave oven.
A radar sends out microwaves, which get reflected by other objects. When these reflected signals are detected, the radar operator will get a 'picture' of the surroundings.
When using a satellite phone network to make an overseas call, microwave signals are sent out to space by a large aerial dish to satellites orbiting the earth. These satellites then relay the signals to the receiving dish overseas.
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uses of visible light
In medicine, lasers are used to seal blood vessels. In industry, lasers are used to weld metals together.
In telecommunication, digital signals are sent through optical fibres using short pulses of light.
uses of UV rays
Sunbeds work by exposing the skin to ultra-violet radiation, similar to that found in sunshine. This releases a chemical which causes the skin to tan.
Ultraviolet counterfeit currency detectors are used to detect special inks in the bills that only appear under the proper wavelength of UV light.
A UV sterilizer uses ultra-violet light that kills microorganisms that go through it by altering and damaging their DNA.
uses of x-rays
After the X-rays pass through the baggage, they are picked up by a detector. The "picture" formed on the monitor is used by airport staff to determine if there are dangerous items in the baggage.
When a beam of X-rays strike a crystal, the crystalline atoms "spread" the X-rays into many specific directions. The pattern of the "spread" can be studied to understand the crystal structure.
On a photographic film, dark areas show where the X-rays have passed through soft body tissues. White areas show where denser material, such as bones, have absorbed the X-rays.
An image of varying densities will show up on film according to the amount of X-rays that reach each area.
uses of gamma rays
Manufacturers use gamma rays to check for cracks or flaws in their products. Similar to X-rays (but more powerful), gamma rays take pictures of the inside of products to show flaws that are not visible from the outside.
Medical instruments are sealed in an air-tight bag and then placed in a very large field of radiation that can penetrate the bag to kill bacteria.
Because gamma rays kill bacteria and cells, they have been used to treat certain types of cancer. In a controlled procedure, multiple concentrated beams of gamma rays are focused onto a tumor to kill the cancer cells.