Electromagnetism: Electromagnetic Force, Characteristics and Faraday's law

Electromagnetism expresses the electromagnetic force that exists between electrically charged particles. Electromagnetic fields, such as magnetic fields, electric fields, and light, are all representations of electromagnetic force, which is one of the four fundamental forces. Electromagnetism can be defined as a process wherein a magnetic field is produced by introducing the current in the conductor.

Electromagnetic forces are carried by electromagnetic fields which are made up of electric fields and magnetic fields together. It is also responsible for the formation of electromagnetic radiation, like light. Electromagnetic forces can be defined as a type of physical interaction which occurs between electrically charged particles. It can be seen to act between charged particles and is typically a combination of magnetic and electrical forces together. Electromagnetic forces are either attractive or repulsive in nature.

Read More: Electric Currents

Key Terms: Magnetic Fields, Electric Fields, Electromagnetism, Electromagnetic Induction, Faradays’s Law, Lenz’s Law, Electric Force, Current, Conductor

What is Electromagnetism?

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Electromagnetism can be defined as the process in which a magnetic field is created by introducing the current in the conductor. A conductor generates magnetic lines of force of conductor when it is electrically charged. It's the fundamental reason that electrons are attached to the nucleus and are responsible for the nucleus' entire structure. Electromagnetism can also be defined as a phenomenon of the interaction between electric currents or fields and magnetic fields.

For instance, if positive charges are moving in a wire, it releases the magnetic field along with the wire, and the direction of magnetic lines, as well as force, can be determined by using Fleming’s right-hand rule.

What is Fleming’s Right-hand Rule?

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Explanation of Electromagnetism

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Electricity and magnetism were thought to be different forces. It wasn't until the nineteenth century that they were eventually recognized as linked events. Albert Einstein's special theory of relativity proved that both are elements of the same event.

• Electric and magnetic forces behave very differently in practice and are described by differential equations.
• Electric charges produce electric forces whether they are stationary or moving. Magnetic forces are only produced by moving charges and only act on moving charges.

• As the forces act on the individual charged constituents, electric phenomena can occur even in neutral matter.
• The electric force, in particular, is responsible for the majority of atoms' and molecules' physical and chemical properties. When compared to gravity, it is immensely powerful.
• Electric phenomena are responsible for the lightning and thunder that accompany certain storms on a smaller scale.

Read More: Inductance

• The electric and magnetic fields are places where electric and magnetic forces can be found. These electric and magnetic fields are basic in nature, and they can exist in space without being affected by the charge.
• Independent of any external charge, electric fields can produce magnetic fields and vice versa. As physicist Michael Faraday discovered in his work that is the foundation of electric power generation, a changing magnetic field produces an Electric Field.
• A fluctuating electric field, on the other hand, produces a magnetic field, as Scottish physicist James Clerk Maxwell discovered.

Read More: Energy Consideration - A Quantitative Study with Lenz Law

Electromagnetic Waves

Radio and television waves, microwaves, infrared rays, visible light, UV rays, X-rays, and gamma rays are examples of electromagnetic waves that propagate across space independent of matter. All of these electromagnetic waves travel at the same speed namely, the velocity of light. Only the frequency at which their electric and magnetic fields oscillate differs between them.

Even though Maxwell's equations still provide a thorough and elegant description of electromagnetic phenomena down to the subatomic scale, they do not include it. In Einstein's very special relativity theory, electric and magnetic fields were unified into a single field, and the velocity of all matter was confined to the velocity of electromagnetic radiation.

The strong force, which is responsible for the energy released in nuclear fusion, and the weak force, which is observable in the radioactive disintegration of unstable atomic nuclei, are the two extra forces. The electroweak force has been created by combining the weak and electromagnetic forces into a single force. 

Read More: Lenz Law and Conservation of Energy

What is Electromagnetic Induction?

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A conductor generates voltage i.e, electricity when it is placed and moved through the magnetic field, this principle is known as electromagnetic induction. The voltages that are generated will be based on the speed of the conductor moving through the electric field. Thus, the faster the speed of the conductor, the greater will be the induced electricity or voltage.

 Electromagnetic Induction

Electromagnetic Induction Formula

Induced voltage can be expressed by the given relation:

Here,

• e = Induced voltage (in volts)
• N = Number of turns in the coil
• Φ = Magnetic flux – Amount of magnetic field at surface (in Webbers)
• t = Time (in seconds)

Faraday’s Law and Electromagnetism

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Based on Faraday’s law, the relative motion between magnetic field and conductor, the flux linkage changes which induces a voltage across the coil. For instance, the DC generator functions on the principle of Faraday’s law of Electromagnetic induction through mechanical energy is converted to electrical energy.

Galvanometer

Features of Electromagnetism

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Electromagnetic waves are ubiquitous in everyday life. Some important features of Electronagnetis are:

• Electromagnetic waves can be propagated via oscillating electric and magnetic waves at right angles to one another.
• Electromagnetic waves typically show the properties of interference and diffraction.
• Electromagnetic waves travel at a speed of 3 × 10⁸m/s (in vacuum).
• These are transverse waves.
• The relationship between the wavelength (λ) and frequency (c) of an electromagnetic wave is given as follows: c = v λ

The following are the main characteristics of an electromagnet:

1. An electromagnet is only temporary in nature.
2. Soft iron makes up the core of an electromagnet.
3. The strength of the magnetic field can be altered.
4. An electromagnet can be simply demagnetized by shutting off the current.
5. The polarity can be altered between positive and negative.

Examples of Electromagnetism

Some of the major examples of Electromagnetism are:

• Permanent magnetic speakers

Electromagnetic devices include permanent magnetic speakers, which are often seen in televisions and radios. Let's have a look at how these devices, which work on the principle of electromagnetism, work. The speakers are created in order to transform electrical waves into audible sounds. A permanent magnet is connected to a metal coil that produces a magnetic field when current runs through it.

• Electric Motors

Electric motors are used in electric fans, blowers, and other cooling systems. These motors operate on the electromagnetic induction principle, which is a branch of electromagnetism. According to the Lorenz force principle, the magnetic field produced by the electric current moves the electric motor in any electrical equipment. The size, rating, and cost of these motors vary depending on the application.

• Medical System

Electromagnetic fields are being used in a variety of innovative medical devices, including cancer hyperthermia therapies, implants, and magnetic resonance imaging (MRI).

Frequencies in the RF spectrum are typically utilized in medical applications. In MRI scans, advanced technology that uses electromagnetism to scan minute aspects of the human body is used. Electromagnetic therapy is a type of alternative medicine that purports to treat disease by exposing the body to pulsed electromagnetic fields or electromagnetic radiation. Nervous problems, diabetes, spinal cord injuries, ulcers, asthma, and other maladies are treated using this sort of treatment.

• Electric Bell

The electric doorbell is a basic circuit that makes a sound when the circuit is completed and the button is pressed. The simplicity of doorbells is what makes them such a marvel. To comprehend the operation of an electric bell, you must first comprehend the concept of an electromagnet.

An electromagnet is a type of magnet that generates a magnetic field using an electric current. When an electromagnet is subjected to electrical effects, it behaves like a regular magnet (generating magnetic fields). When the electricity to an electromagnet is turned off, the magnetic field is also turned off. So, along with the Armature, Spring, Armature rod, Hammer, and Gong, an electromagnet is a vital component of an electric bell.