The electromagnetic radiations are stream of photons travelling in waves through vacuum. That is, they don’t need any medium to travel unlike sound waves. An electromagnetic spectrum consists of all forms of electromagnetic radiations arranged from lowest energy (longest wavelength) to highest energy (shortest wavelength).
· The low frequency radio waves are not visible to our eyes and mainly used for communication. They transmit audio signals to radios, audio and video signals to our televisions and signals to our cell phones. Prolonged exposure to these waves has an impact on our health.
· Microwaves are used for cooking food, satellite transmissions and by radars used in aircrafts.
· Infra Red or IR rays lies just below the visible light. They are used in TV remotes for changing channels. Heat given out by IR rays is used in therapies in healing body pain and injuries.
· Only part of the EM spectrum that is visible to our eyes is Visible light. The lamp that glows in our houses, the white light from sun all fall under visible range of frequencies.
The radiations that have higher energy levels are dangerous. Large doses of these radiations can damage the retina in the eyes, cause cancer and leukemia.
· Ultraviolet or UV rays are needed by our body to synthesize vitamin D. Hospitals use UV rays to sterilize surgical equipments and kill microbes.
· X-rays are high frequency rays that are very much useful in medical field to examine inner parts of our body.
· Gamma rays are used in industry to inspect welds.
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