Elecromagnetic Spectra, EMR
The entire range over which the electromagnetic radiation exists is known as electromagnetic spectrum. This electromagnetic spectrum ranges from very short wavelengths (including gamma and x-rays) to very long wavelengths (including microwaves and broadcast radio waves). The following chart displays many of the important regions of this spectrum.
Fig. 2: The electromagnetic spectrum
According to the fig. 2, the major characteristics of various spectrum regions are as follows:
- γ-rays- It lies between 0.2 to 10 nm. They are the shortest waves. They are emitted by atomic nuclei, involving energy changes of 109 to 1011 joules/gram atom.
- x – Rays – it lies between 10 nm TO 100 nm. It is emitted or absorbed by movement of electrons. X- Rays are used for diagnostic purpose.
- visible and ultraviolet region- UV radiation lies between 200 nm to 400 nm. Visible region lies between 400 nm to 800 nm.
- Infrared region- infrared region is further divided in three regions.
Near infrared region lies between 800 nm to 4000 nm.
Middle infrared region lies between 4000 nm to 25000 nm.
Far infrared region lies between 25000 nm to 100000 nm.
- Microwave region- This region lies between 106 nm to 107 nm. Microwaves are used in telecommunication.
6. Radio frequency region- radio frequency region lies between 107 nm to 109 nm.