Electromagnetism, a macroscopic theory, is a branch of science that is composed of two different aspects, namely, electricity and magnetism. Electromagnetism deals with the magnetic forces (interactive forces) that exist between two electrically charged particles. These interactive forces contain both components (electricity and magnetism) and are therefore known as electromagnetic forces, also known as the Lorentz force. These forces may be either attractive or repulsive in nature. The structure of an atom is the best example of an electromagnetic force, as the interactive forces/electromagnetic forces between the positively charged nucleus and the orbital electrons binds the charged particles together and maintain the stability of an atom.
Electromagnetic forces are one of the four fundamental forces of nature. The electromagnetic force is defined as the interactive force (magnetic lines) that occurs when a current is allowed to pass through a conductor. These electromagnetic forces are carried by electromagnetic fields, composed of electric and magnetic fields, that are responsible for the generation of electromagnetic radiation. Radio Waves, TV waves, Radar waves, Heat (infrared radiation), Light, Ultraviolet Light, X-rays, and Short waves are some examples of electromagnetic radiation.
Electromagnetic induction, on the other hand, is defined as the electricity generated, because of the electromotive force, due to changing magnetic fields. Changing magnetic fields move electric charges. This either happens when a conductor is placed in a moving magnetic field or when a conductor is constantly moving in a stationary magnetic field. Electric generators, Electromagnetic forming, Graphics tablets, Hall effect sensors, Induction cooking, Induction motors, and Induction sealing are a few examples of electromagnetic induction.
Examples of Electromagnetism
Electromagnetism holds significant importance in a wide variety of fields including, industrial, transportation, and medical fields. Apart from this, we cannot deny the fact that we also rely on electromagnetic appliances on a daily basis to some extent. Some of the daily life examples of electromagnetism are explicated as follows-
1. Kitchen Microwave Ovens
Microwave ovens, also known as electric ovens, are widely used to heat or cook the food by high-frequency electromagnetic waves. Ovens use electromagnetic oscillators which produce electromagnetic waves in the wavelength range of 1m to 1mm. These electromagnetic waves are called microwaves and are produced only when the oven is operating. The food absorbs these microwaves and generates heat, which is responsible for cooking. The commonly used wave frequency for microwave ovens is roughly 2,450 megahertz (2.45 gigahertz). Other than microwaves, other home appliances such as washing machines, vacuum cleaners, food blenders, ovens, microwaves, dishwashers, hairdryers, tumble dryers, etc., contain electric motors, which also work on the basic principle of electromagnetism.
2. Entertainment gadgets
Entertainment gadgets, such as television, mobile phones, and radios, use radiowaves to broadcast or communicate their signals. Radiowaves hold the longest wavelength in the EM spectrum with a frequency range of 104 to 1012 Hertz. These waves can be easily transmitted through the air, and they do not cause any harm to the human body. These devices use radiowaves and convert them into mechanical vibrations for the production of sound waves. Television waves have a wavelength range of 50 centimeters to about 10 meters, which is shorter than the wavelength used in radios, therefore TV waves diffract less. Mobile phones, also known as low-powered radiofrequency transmitters, have approximately 10-1000 m wavelength and operates between the frequency range of 450 and 2700 MHz.
3. Maglev Trains/Magnetic suspension trains
Maglev trains, also known as magnetic levitation trains, is a land transportation vehicle that is supported by either attraction or repulsion. This magnetic suspension train uses two sets of magnets, one set is used to repel and push the train up off the track up to 10 cm, and another one moves the train ahead. This magnetic field setup is used to suspend, guide, and propel the train onto the track. These magnetic fields interact with simple metallic loops present in the concrete walls of the Maglev guideway. These metallic loops are composed of conductive materials, like aluminum, and when a magnetic field crosses these loops, an electric current is produced which generates another magnetic field. One vital advantage of using these trains is that they are eco-friendly, as no fuel is being used and thus no air pollution.
Transformers are cylindrical voltage-controlling (increase or decrease) devices used to control the voltage of alternating current. Transformers work on the principle of electromagnetic induction to transfer energy from one circuit to another. The core of the transformer directs the path of the magnetic fields between primary and secondary coils. Once the magnetic field reaches the secondary coil, it forces electrons to move and an electromotive force is generated which produces an electric current.
Microphones, the most commonly used device nowadays, works on the principle of electromagnetic induction. It converts mechanical energy (sound waves) into electrical energy (audio signals). Sound waves hit the diaphragm present in the microphone which vibrates and converts is converted into electrical energy through magnetic coils.
6. Electric Fan
Electric fans work on the basic principle of electromagnetic induction with the help of an electric motor. An electric motor contains a coil of wire around a metallic core. When current is passed through this coil, a magnetic field is created which further helps in the clockwise rotation of the fan blades.
7. Electric Door Bell
Electric doorbell works the electromagnetism mechanism. It contains an electromagnet, an artificial magnet, in which the flow of current produces magnetic fields. In this device, the wire wound around a coil acts as the electromagnet. These generated magnetic fields last as long as they have access to the flow of current. When the electric power supply is stopped, it will stop behaving like a magnet.
8. Magnetic Card Reader
When the magnetic stripe is swiped through the scanner, an electromotive force is induced due to the change in magnetic flux (in one direction). Therefore, electric car readers, such as ATM cards, and credit cards are applications of electromagnetic induction.
9. Storage and recording Devices
Tape recorders, video cassette recorders, magnetic tapes, and video cassette players employ the content of electromagnetism to record data. Iron oxide and chromium dioxide are usually used for coating magnetic materials in cassette tape recorders. As the tape passes the five magnetic heads of a tape recorder, the sound is recorded, replayed, or erased according to the heads that are activated.
Hard disks also use the electromagnetism phenomenon to store data to a large extent. They consist of a platter and an actuator. A platter, a hard ferromagnetic material, is a place where all the files and data are stored, whereas an actuator arm is a piece that writes the data and magnetizes certain parts of the platter, giving it a value of 0 or 1.
10. Digital Camera
Infrared radiations are usually used in cameras for clicking pictures. A digital camera is an application of electromagnetic induction and is highly preferred over conventional cameras.
11. Induction Cookers
An induction cooker, a kitchen appliance, works on the basic principle of electromagnetic induction and is widely used in homes nowadays. It is used to transfer electrical energy by induction from a coil of wire into a metal vessel. The coil is placed under the cooking surface and a high-frequency alternating current is passed through it. The current in the coil produces a magnetic field which in turn induces heat and the food is cooked.
12. Electric Generators
An electric generator, also known as a dynamo, is a device used to convert mechanical or chemical energy into electrical energy. These works on the principle of electromagnetic induction. The internal structure of a generator constitutes a conductor coil and a magnet. The conductor coil is wound on the surface of a metal core and is rotated between the poles of the magnet. The arrangement of the conductor coil and core is known as an armature. Horse-shoe-shaped magnets are used in electric generators. Due to alterations in magnetic fields, caused by the movement of the coil, an interference takes place in the electrons. This interference results in the conversion of mechanical energy into electrical energy. An electric generator acts as an uninterrupted power supply device and serves to be helpful in case of power cuts or power outages.
13. Electric motors
Electric motors also work on the principle of electromagnetism, which converts electrical energy into mechanical energy. Motors are usually employed in devices that require circular or rotatory movements as mechanical energy. Motors are an example of electromagnetism and are also the most commonly used in day-to-day life. When a current is allowed to pass through the coil, present in electric motors, a magnetic field is generated. This magnetic field induces interaction forces (attractive or repulsive), thus resulting in the spilling or rotation of the motor blades.