A static charge produces an electric field around it. Again, when a charge is in motion, it produces a magnetic field around it. But how electromagnetic waves are produced? An accelerating charge produces electromagnetic waves where both the electric field and magnetic field propagate together in an electromagnetic field. Electromagnetic waves are nothing but the flow of electric and magnetic energies in the electromagnetic field. In this article, we’re going to explain all 7 types of electromagnetic waves with their origin, wavelengths and uses.
Contents in this article:
- What is electromagnetic wave?
- Origin of electromagnetic wave
- Properties of electromagnetic wave
- Types of electromagnetic waves in physics
- Is light an electromagnetic wave?
- Spectrum of electromagnetic wave
- use of electromagnetic waves
Definition of Electromagnetic wave in Physics
Time-varying electric field produces a magnetic field. Similarly, a varying magnetic field can produce an electric field. If varying electric field and magnetic field exist in a place, they flow together in the form of a wave in every direction around that place. This wave is called an electromagnetic wave.
The term electromagnetic arises from the terms electric field and magnetic field. Electromagnetic waves consist of both electric and magnetic fields. The resultant field where the electromagnetic wave propagates is known as the electromagnetic field.
How are electromagnetic waves produced?
Electromagnetic waves are produced by an oscillating or accelerating charge. When an electric charge oscillates, a varying electric field arises. This varying electric field produces a varying magnetic field. As a result, an Electromagnetic wave develops.
Properties of Electromagnetic waves
The properties of electromagnetic waves are as follows –
- Electromagnetic waves consist of both electric and magnetic fields in it.
- Electric field, magnetic field and the direction of propagation of wave are mutually perpendicular to each other. Thus, electromagnetic waves are transverse waves.
- The equations for electric field and magnetic field are as E = E0 sin(wt – kx) and B = B0 sin(wt – kx). Where the wave is propagating along +x direction. If E-field is varying along the y-axis then the B-field will vary along the z-axis as they are mutually perpendicular.
- In an electromagnetic wave, the magnitude of electric field is c times the magnitude of magnetic field. Here c is the speed of light in free space which is equal to 3×108 m/s.
- The phase difference between the electric field and magnetic field in an electromagnetic wave is zero. That means they are in phase.
- The speed of an electromagnetic wave in free space is the same as the speed of light in free space (3 × 108 m/s).
Examples of electromagnetic waves in physics
There are seven electromagnetic waves in the electromagnetic spectrum. These are –
- Radio wave
- Infrared wave
- Visible rays
- Ultraviolet (UV) rays
- Gamma rays
All types of electromagnetic waves with their wavelengths and uses
In the spectrum of electromagnetic radiation, one can observe seven waves of different wavelengths and frequencies. They can have different sources and different uses. The list of electromagnetic waves with their uses is given below.
If an accelerating charge moves through a conductor, a radio wave produces. This type of wave has a wavelength in the range of 10000 m to 0.1 m. Radio waves are used in Radio, Mobile phones, TVs etc. Radio waves are also used in satellite communications. We have a detailed article on the characteristics of radio waves which can give a better idea about radio waves.
Different electronic gadgets produce Microwaves. The wavelength range for Microwaves is from 0.3 m to 10-4 m. Microwaves are used in Micro-oven and RADAR systems.
The vibration of molecules of matter at room temperature generates Infrared light. The wavelength range for Infrared light is from 10-3 m to 4×10-7 m. Infrared light has wide uses in medical field and photography.
When an electron jumps from a higher orbit to a lower orbit of an atom, it releases energy in the form of photons or light. This is nothing but visible light. Visible light has a wavelength range from 4×10-7 m to 7×10-7 m. Human eyes can see in this wavelength range of light.
Ultraviolet rays (UV rays)
The main source of UV rays is the Sun. Ultraviolet rays have a wavelength range from 7×10-7 m to 10-10 m. UV rays cure skin disease. But high-intensity UV rays cause skin cancer. Ozon layer protects us from high-intensity UV rays coming from the sun.
X-rays can be produced by colliding a target atom with a highly energetic electron. The wavelength range for X-rays is from 0.01 angstrom to 10 angstrom. X-rays have wide uses in medical field, in paper cutting, as a barcode reader, etc.
Gamma rays are produced from radioactivity. It has the smallest wavelength and higher frequency. Therefore, the energy of gamma rays is much higher than other electromagnetic waves. Gamma rays have a wavelength smaller than one angstrom.
Uses of Electromagnetic waves
Electromagnetic waves have wide uses in communication systems. In TV, radio, RADAR, Satellites etc. all the signals are transferred in the form of electromagnetic waves. Electromagnetic radiations have applications in medical science as well.
Some useful questions
1. Which electromagnetic wave has the highest frequency?
Answer: Gamma ray. It has the highest frequency and smallest wavelength.
2. Which electromagnetic wave has the shortest wavelength?
Answer: Gamma ray. It has the shortest or smallest wavelength and highest frequency.
3. What electromagnetic wave travels fastest?
Answer: All electromagnetic waves have the same velocity which is equal to the speed of light. So, all electromagnetic waves move at the same speed in the same medium.
4. Is the light an electromagnetic wave?
Yes, Light is an electromagnetic wave. Its energy flows in the form of a Transverse electromagnetic wave. Light has all the properties of an electromagnetic wave as discussed above.
Read the article on light energy and its properties.
This is all from the article on all 7 types of electromagnetic waves with their wavelengths and uses. If you have any doubts you can ask in the comment section.
- Characteristics of radio waves – wavelength, color and uses.
- Electric field and electric field intensity
- Properties of electric field lines
- Origin of Magnetic field
- Electromagnetic Induction