A wave is a vibration that is propagated in space. As its name suggests, an electromagnetic wave is formed when an electric field combines with a magnetic field, both being perpendicular to each other. The credit for the study of its origin and theory, is given to James Clark Maxwell and Heinrich Hertz. It is defined as a wave comprising an electrical and a magnetic component at right angles to one another but which are in phase and have the same frequency.
Electromagnetic waves are classified on the basis of their wavelength. Wavelength is defined as the distance between the peaks or the crests of a wave.
Radio waves not only transmit radio signals, but also carry signals for our televisions and cellular phones. Their wavelength is as low as a few millimeters and as high as hundreds of kilometers. The frequencies vary between few kilohertz to a few tetra-hertz.
The use of this waves in cooking has become so common that these have become a household name in cooking appliances. The wavelength of these waves is between a few hundred millimeters. Microwaves are also used for communication purposes like telephonic calls and computer data. As microwaves have the ability to penetrate light, dust, rain etc. these are used to view the earth from outer space.
The wavelength of infrared rays lies between 1 millimeter to 750 nanometers. The remote control of your television also uses infrared waves. Apart from remote controls, infrared waves also find their use in night vision goggles.
Visible light as the name suggests, is the only form of electromagnetic radiation that we can see. We see these colors as the colors of the rainbow as VIBGYOR, with each alphabet representing a color. In VIBGYOR, the colors are violet, indigo, blue, green, yellow, orange and red. The wavelength is in the decreasing order from red to violet. When all of these colors with their different wavelengths come together, they form visible light.
Ultraviolet rays are invisible to the human eye. The wavelength of ultraviolet waves is around 10 to 380 nanometers. Ultraviolet rays are dangerous to skin and can cause sunburns and skin cancers. These are prevented from reaching the surface of the earth by a layer known as the ozone, but still some of these harmful rays enter earth's atmosphere through a hole in the ozone.
These waves have smaller wavelengths with more energies. These were accidentally discovered by Wilhelm Conrad Roentgen, while he was working on vacuum tubes. As the origin of the waves was unknown, he called them X-rays. The X-rays have wavelengths between about 10 nanometers (10×10-9 meters) and 10 picometers (10×10-12 meters). We all know how important they are in the field of medical science as they help in revealing fractures and inner parts of the body.
Gamma rays have the highest energy and shortest wavelength in the electromagnetic spectrum. These rays are produced by explosions, destruction of atoms and radioactive decay. The wavelengths are about 10×10-12 meters. These are used to treat cancerous cells, due to which they find their use in medical science.
As we mentioned above, the electromagnetic waves properties allow them to be used in a variety of fields from cooking to medicinal. But besides these properties, they also have some dangerous effects, as people whose work demands them to be exposed to these waves, may suffer from tumors, intestinal problems, constipation, etc. So proper care and precaution must be taken to ensure that no long-term damage is caused to the body.