Electromagnetic Fields and Radiation

Electromagnetic radiation is a form of energy that comprises electric and magnetic waves. It propagates in free space and contains neither mass nor charge but carries energy as a photon packet. The energy associated with electromagnetic radiation is directly proportional to the frequency from extremely low frequencies to visible light and above. The highly low-frequency electromagnetic field is generated by the electrical devices and power systems, while the radio and microwave signal radiates by the mobile tower, microwave oven, heater, radar, etc. The extremely high-frequency radiation emitted from medical devices, radioactive decay, nuclear weapons, etc. Therefore, environmental exposure to electromagnetic radiation increases gradually due to increasing electricity demands, advanced technologies, mobile communications, etc. However, exposure to electromagnetic radiation has an adverse biological effect depending on the current intensity, strength of the magnetic field, and duration of exposure. This book chapter introduces electrostatics and magneto-statics, the formation of electromagnetic fields and waves, frequency spectrum, source of radiations, and their exposure limits.