The EM spectrum consists of 7 different types of electromagnetic waves which are discussed below. Electromagnetic waves are classified according to their frequency or wavelength. All EM waves that are transverse in nature are made up of photons of a specific wavelength that travel through space until they interact with the matter.
What Is Electromagnetic Waves?
Electromagnetic waves are also known as EM waves that are formed when an electric field comes in contact with a magnetic field. Electromagnetic waves are a composition of oscillating electric and magnetic fields that are perpendicular to each other. The direction of electromagnetic waves is also perpendicular to the direction of both the electric and magnetic fields.
EM waves are produced by the motion of electrically charged particles that are capable of traveling through a vacuum as well as through the air. The speed of electromagnetic waves through a vacuum is the same as the speed of light, which is about 300,000,000 meters per second(m/s).
The theory of EM waves was developed by a scientist named James Clerk Maxwell in the 1860’s and 1870’s which are now known as “Maxwell Equations.” These equations of Maxwell are applied to the generation and reception of radio waves by a German scientist, Heinrich Hertz, so the unit of frequency of radio waves is Hertz (one cycle per second ).
Types of Electromagnetic Waves
Radio waves are the lowest-frequency and highest wavelength of the seven bands of the waves on the electromagnetic spectrum. As the wavelength of the radio waves is greater they are used to transmit information in a radio communication system such as television, radio or cellphones, a communication satellite, and wireless networking, The wavelength of radio waves is approximately 103m and energy between 3khz and 300GHz.
In radio communication systems these waves are artificially created by an electronic device called transmitter which is applied to an antenna. The antenna is therefore responsible for the emission and reception of radio waves. The radio waves are modulated with the information-bearing signals in a transmitter by varying either the amplitude, frequency, or phase which are now connected to the antenna. Now the radio waves radiate away from the antenna which eventually reaches the radio receiver and the information is extracted by demodulation in the receiver.
The allocation and distribution of radio waves are strictly regulated by the government as well as the International Telecommunication Union(ITU).
Microwaves are the highest frequency of radiowaves or the second-lowest frequency waves in the electromagnetic spectrum. Microwaves have frequencies between 3GHz and 30THz and wavelength of about 10mm to 100 micrometer of the electromagnetic spectrum.
Due to their higher frequency, microwaves can penetrate through clouds or dust, smoke, and light rain. There are various uses of microwaves such as cooking food, broadcast information through space, predict weather forecasts, and communicate with satellite and spacecraft.
Infrared waves are the range of EM spectrum between microwaves and visible light. It has a wavelength of about 100 micrometers to 740 nanometer and frequency lies between 30THz to 400THz. There are two types of infrared waves “near” infrared and “far” infrared. Near-infrared waves are closer to visible light which is used in TV remote and imaging. Far infrared waves are further away from visible light which is used in night vision goggles. Infrared waves are produced by any object that gives off heat including the human body.
Visible Light Rays
Visible light rays are a type of electromagnetic radiation that is found in the middle of the electromagnetic spectrum between IR and UV. It has a frequency of about 400THz to 800THz and wavelength of about 740nm to 380nm. The only electromagnetic wave that can be seen with the naked eye is visible light rays. This part of the spectrum includes a range of different colors each representing a particular wavelength.
The color of any object is due to the reflection of a certain wavelength of visible light. Visible light(white light) constitutes 7 different colors as seen in a rainbow. Each color has a different wavelength such as red has the longest wavelength whereas the violet hues the shortest wavelength in the spectrum.
Ultraviolet waves are those electromagnetic waves which have a shorter wavelength than visible light but longer than X-rays. The EM radiation with a frequency of 8×1014 to 3×1016 is called ultraviolet and the respective wavelength of these waves is about 380nm to 10nm. “Hot” objects in space such as sun and star and even high-temperature processes emit UV radiation.
These radiations are the cause of sunburns and even cancer in living organisms although it has certain benefits. It is used in learning the structure of galaxies, Hubble Space Telescope uses UV light to see far objects in space. UV radiation is also the cause of sunburn and even cancer in living organisms. That is the reason why sunscreen is very important. Luckily we’re protected by the ozone layer and the rest of the atmosphere, which filters out most UV rays before they cause any real damage. Some insects are able to see UV rays such as bumblebees.
X-rays are those electromagnetic radiations which have a shorter wavelength and extremely high energy than UV. X-rays have frequencies ranging from 30 petahertz to 30 exahertz and wavelength from 0.01nm to 10nm. X-rays with wavelength under 0.2-0.1nm are called “hard ” as they are used in the hospital to see the structure of bone and even in the airport to see inside the luggage.
Natural sources of X-rays include cosmic phenomena such as pulsars, supernova, and blackhole. Many scientists consider these radiations more as particles than waves due to its shorter wavelength with a typical size of about 0.1nm(width of an atom).
The EM waves with the highest frequency in the electromagnetic spectrum are gamma waves. They have a frequency more than 30 exahertz and wavelengths of under 10 picometers. Gamma rays are produced in high energy nuclear explosions, radioactive decay, and lightning. They are also emitted during a supernova, black hole, and most energetic cosmic objects such as pulsars.
Gamma rays are used to see inside your body by doctors and for the treatment of cancer as they cause damage to living tissue. such as cancerous cells.
All radio waves (e.g., commercial radio and television, microwaves, radar), infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays are all part of the electromagnetic spectrum, which extends from the lowest to the highest frequency (longest to shortest wavelength).
All electromagnetic waves are transverse waves; they may travel through a vacuum; and they travel at the same speed in a vacuum, 300,000,000 m/s.