Electromagnetic power is the force on the particles due to Electromagnetic Field . Electromagnetic force is one of the 4 fundamental forces which also include Strong nuclear force, weak nuclear force and gravitational force. An electromagnetic field is not visible to the naked eye. Electromagnetic Induction<span class=] "] is the generation of magnetic field due to change in electric field and vice versa. This phenomenon exists because electromagnetism manifests as both electric and magnetic fields. Electromagnetism is the force which holds the protons and electrons together in an atom, which is the building block of a molecule. This concept was discovered by Hans Christian Orsted on 21 April, 1820. He noticed that when a compass was exposed to electric current it deflected from magnetic north. This convinced him that there is a magnetic field radiation around every current carrying wire. Electromagnetic power is responsible for photoelectric effect, and all types of radiations from radio waves to gamma rays.
The natural sources of electromagnetic fields include thunderstorms and the earth’s magnetic field. The man made sources include X-rays, electricity out of every power socket, and high frequency radiowaves like in TV stations, Radio antennas or Mobile phone base stations are sources of electromagnetic fields .
Einstein's theory says that light exists not only as a wave but also as a particle. This dual nature of light can change between being a wave or a particle depending on the way it is measured. The particulate nature of light is due to small packets of energy called photons. This theory of You do not have access to view this node was put forth by Einstein which extended its insight to Plank’s UV catastrophe theory that hot objects emit radiation in discrete packets of energy which is proportional to the frequency of the electromagnetic wave. The overall sum of this energy is equal to the total energy emitted as Black body radiation. Both these theories were key elements for the invention of quantum theory of electromagnetism. This theory is called quantum electrodynamics.
Electromagnetic spectrum is a series of waves with similar frequencies that travel at an enormous speed, the speed of light. The frequency describes the number of oscillations per second, and wavelength describes the distance between two waves. Hence wavelength and frequency are inseparable: the higher the frequency the shorter the wavelength. Hence various forms of electromagnetic fields are different.
Electromagnetic waves are carried as particles called quanta. If the energy in the quanta can break the bond between molecules, it is called Ionizing radiations. For example X-rays, cosmic rays and gamma rays have this property. They also affect the biological tissues. The non-Ionizing portion includes the extremely low frequencies. It usually includes frequencies in the range of 300 GHz. This range includes radiowaves, microwaves, IR and visible rays. They do not harm the biological tissues. Radiofrequencies are an important part of this spectrum. Radiofrequency radiation is measured using power density. If the person is near to the radiofrequency source then specific absorption rate is used.
Yes, some of the waves are life threatening. As explained earlier ionized radiations are capable of breaking through molecular bonds, which implies they can affect the biological tissues. X-rays have the potential to break or disrupt DNA, which are the building blocks of a cell. Excessive exposure can cause life threatening diseases like cancer. There are numerous studies being conducted on the effects of EMF on human beings. There seems to be an increase in the number of people suffering with asthma who were exposed to EMF more frequently but the studies aren't conclusive that EMF definitely causes this. As to why EMF is harmful is not yet fully known but it seems to disrupt the communication between cells which impacts the proper functioning of the immunity system. Pregnant women should avoid being exposed to EMF or at least try to limit the exposure.