An accelerating charged particle produces an electromagnetic (EM) wave. Electromagnetic waves are electric and magnetic fields traveling through empty space with the speed of light c. A charged particle oscillating about an equilibrium position is an accelerating charged particle and if its frequency of oscillation is f, then it produces an electromagnetic wave with frequency f.
Electromagnetic waves transport energy through space which can be delivered to charged particles a large distance away from the source.
Accelerating charges produce changing electric and magnetic fields. Changing electric fields produce magnetic fields and changing magnetic fields produce electric fields. This interplay between induced electric and magnetic fields leads to propagating electromagnetic waves through free space.
Gamma (γ) rays
Gamma rays have the smallest wavelengths and the most energy of any wave in the electromagnetic spectrum.
They results from energy changes occurring in the nuclei of the radioactive atoms.
The term gamma ray was coined by British physicist Ernest Rutherford in 1903 following early studies of the emissions of radioactive nuclei.
They are produced by the hottest and most energetic objects in the universe, such as neutron stars and pulsars, supernova explosions, and regions around black holes.
On Earth they are generated by nuclear explosions, lightning, and radioactive decay.
X-rays
They are produced when a high energy electrons bombard a metal target in an X-ray tube. They are also said to originate from fast moving electrons when they are suddenly stopped by a metal target.
Ultraviolet(UV) Radiation
They are produced by the sun, sparks and mercury vapour lamps due to large energy changes in the electrons of an atom. UV radiation is produced either by heating a body to an incandescent temperature, as is the case with solar UV, or by passing an electric current through a gas, usually vaporized mercury. Electrons in the mercury atoms gain energy from the current then emit it again as UV.
Visible light
A visible light stimulus is electromagnetic radiation that can be perceived visually by an organism(Royal Society of chemistry).
Visible light is composed of seven different colours with violet having the least wavelength and red having the highest. It is naturally produced by sun, hot objects, lamps,candles, electric bulbs, laser beams e.t.c.
Visible light is created the same way all other ElectroMagnetic waves are produced from emission of radiation while an electron jumps from an higher energy state to a lower one. In this process all shorts of EM waves are created but we can see only the visible light spectrum.
Infrared Radiation(IR)
It is produced as a result of small energy changes of an electron in an atom or molecular vibrations which happens in the sun, fire or any hot objects.
Any material with temperature above absolute zero emits InfraRed and so IR radiations are produced in all matter by means molecular vibration. Molecular movement causes infrared emission of different wavelengths and frequencies but each wave is proportional to the temperature of the body where higher the temperatures produces radiations of higher frequency and hence with shorter wavelengths.
Microwaves
They are produced by special vacuum tubes called magnetrons in microwave ovens or with a maser that operates on the ballistic motion of electrons controlled by magnetic or electric fields
Microwaves are produced by special vacuum tubes like the klystron, magnetron and Gunn diode where the frequency of microwaves is selected to match the resonant frequency of motor wall so that the energy is transferred efficiently to the kinetic energy of the molecules.
Radio Waves
Radio waves are produced artificially by time-varying electric currents,
consisting of electrons flowing back and forth in a specially-shaped metal conductor called an antenna. An electronic device called a radio transmitter applies oscillating electric current to the antenna, and the antenna radiates the power as radio waves.
Radio waves are received by another antenna attached to a radio receiver. When radio waves strike the receiving antenna they push the electrons in the metal back and forth creating tiny oscillating currents which are detected by the receiver. see the illustrations below
Related Topics
- Electromagnetic spectrum
- Angular velocity
- Calculating speed of a wave
- Types of waves
- Characteristics of a wave motion
- Trigonometric ratios
- Equation of a circle