Dear Readers,
Electromagnetic Radiation is a form of energy that is all around us and takes many forms. EM radiation (the designation 'radiation' excludes static
electric and magnetic and near fields) is classified by wavelength into radio, microwave, infrared, visible, ultraviolet, X-rays and gamma rays.
Electromagnetic Theory
Electricity and magnetism were once thought to be separate forces. However, in 1873, Scottish physicist James Clerk Maxwell developed a unified theory of
electromagnetism.
Important Electromagnetic Rays
Electromagnetic Rays
|
Discovered By
|
Wavelength Range
(in Meter)
|
Frequency Range
|
Remarks
|
|---|---|---|---|---|
| γ-Rays (Gamma Rays) | Henry Becqueral | 10-14 to 10-10 | 1020 to 1018 | Gamma radiation causes damage to living tissue, which makes it useful for killing cancer cells when applied in carefully measured doses to small regions. Uncontrolled exposure, though, is extremely dangerous to humans. |
| X-Rays | Wilhelm Röntgen | 10-10 to 10-8 | 1018 to 1016 | X-rays occupy the same region of the EM spectrum as gamma rays. The only difference between them is their source: X-rays are produced by accelerating electrons, while gamma rays are produced by atomic nuclei. |
| Ultra-Violet Ray | Johann Wilhelm Ritter | 10-8 to 10-7 | 1016 to 1014 | UV light is a component of sunlight; however, it is invisible to the human eye. It has numerous medical and industrial applications, but it can damage living tissue. |
| Visible Radiation | Newton | 3.9x10-7 to 7.8x10-7 | 1014 to 1012 | More generally, visible light is defined as the wavelengths that are visible to most human eyes. |
| Infra-Red Rays | William Herschel | 7.8x10-7 to 7.8x10-3 | 1012 to 1010 | IR rays is invisible to human eyes, but we can feel it as heat if the intensity is sufficient. |
| Microwaves Ray |
-
|
10-3 to 10-2 | 1010 to 1009 | Microwaves are used for high-bandwidth communications, radar and as a heat source for microwave ovens and industrial applications. |
| Short Radio Waves or Hertz Hertzian Waves | Heinrich Hertz | 10-3 to 1 | 1010 to 108 | Radio waves are used primarily for communications including voice, data and entertainment media. |
| Long Radio Waves | Marcony | 1 to 104 | 108 to 106 | Radio waves are used primarily for communications including voice, data and entertainment media. |
★★Questions are there in SSC from this article in GK Section. like ★★
1. Which part of em radiation is used in radar ? ans.- microwave radiation
2. Which part of em radiation is used to kill cancer cell ? ans. -gamma rays
(Shared by our reader "Deepi")
