What is the electromagnetic induction?

Question

Answer

The process of producing induced current in a closed circuit or in a coil by changing the magnetic field linked with the coil is known as electromagnetic induction. ... This process of producing induction current is known as electromagnetic induction.

Answer

Electromagnetic or magnetic induction is the production of an electromotive force across an electrical conductor in a changing magnetic field. Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk Maxwell mathematically described it as Faraday's law of induction.

Answer

**Electromagnetic Induction**

Electromagnetic induction is a phenomenon that occurs when a conductor moving through a magnetic field or when there is a change in the magnetic field around a conductor, induces an electric current or electromotive force (emf) in the conductor. This principle was discovered by Michael Faraday in the early 19th century and forms the basis for many technologies such as generators, transformers, and electric motors.

**Principle of Electromagnetic Induction**

Electromagnetic induction is based on two fundamental principles:

1. **Faraday's Law**: This law states that the magnitude of the induced emf in a circuit is directly proportional to the rate of change of magnetic flux through the circuit. Mathematically, it can be expressed as:

emf = -N(dΦ/dt)

Where emf is the electromotive force, N is the number of turns in the coil, and dΦ/dt is the rate of change of magnetic flux.

2. **Lenz's Law**: According to Lenz's law, the direction of the induced current in a circuit is such that it opposes the change in magnetic flux that produced it. This law is based on the principle of conservation of energy.

For example, if a magnet is moved towards a coil, the induced current will create a magnetic field that opposes the motion of the magnet. Similarly, if the magnet is moved away from the coil, the induced current will create a magnetic field that tries to maintain the magnet's motion.

**Applications of Electromagnetic Induction**

Electromagnetic induction has numerous applications in various fields. Some of the important applications include:

1. **Generators**: Generators are devices that convert mechanical energy into electrical energy using the principle of electromagnetic induction. They are widely used in power plants to generate electricity.

2. **Transformers**: Transformers are devices that use electromagnetic induction to transfer electrical energy from one circuit to another. They are used to step up or step down the voltage levels in power transmission and distribution systems.

3. **Induction Cooktops**: Induction cooktops use electromagnetic induction to heat the cooking vessel directly without the need for a flame or a heating element. The cooktop generates a high-frequency alternating magnetic field that induces eddy currents in the metal of the vessel, heating it up.

4. **Electric Motors**: Electric motors use the principle of electromagnetic induction to convert electrical energy into mechanical energy. They are commonly used in various appliances, vehicles, and industrial machinery.

In conclusion, electromagnetic induction is a fundamental principle in physics that describes the generation of electric currents or electromotive forces in a conductor when it moves through a magnetic field or when there is a change in the magnetic field around it. This principle has revolutionized various technological advancements and finds applications in generators, transformers, induction cooktops, and electric motors.

Answer

Electromagnetic or magnetic induction is the production of an electromotive force across an electrical conductor in a changing magnetic field.  Michael Faraday is generally credited with the discovery of induction in 1831,  and James clerk Maxwell mathematically described it as Faraday's law of induction.

Answer

Answer

If the wire is then wound into a coil, the magnetic field is greatly intensified producing a static magnetic field around itself forming the shape of a bar magnet giving a distinct North and South pole.

Air-core Hollow Coil

The magnetic flux developed around the coil being proportional to the amount of current flowing in the coils windings as shown. If additional layers of wire are wound upon the same coil with the same current flowing through them, the static magnetic field strength would be increased.

Therefore, the magnetic field strength of a coil is determined by the ampere turns of the coil. With more turns of wire within the coil, the greater the strength of the static magnetic field around it.

But what if we reversed this idea by disconnecting the electrical current from the coil and instead of a hollow core we placed a bar magnet inside the core of the coil of wire. By moving this bar magnet “in” and “out” of the coil a current would be induced into the coil by the physical movement of the magnetic flux inside it.

Likewise, if we kept the bar magnet stationary and moved the coil back and forth within the magnetic field an electric current would be induced in the coil. Then by either moving the wire or changing the magnetic field we can induce a voltage and current within the coil and this process is known as

Electromagnetic Induction

and is the basic principle of operation of transformers, motors and generators.

Electromagnetic Induction

was first discovered way back in the 1830’s by

Michael Faraday

. Faraday noticed that when he moved a permanent magnet in and out of a coil or a single loop of wire it induced an

E

lectro

M

otive

F

orce or

emf

, in other words a Voltage, and therefore a current was produced.

So what Michael Faraday discovered was a way of producing an electrical current in a circuit by using only the force of a magnetic field and not batteries. This then lead to a very important law linking electricity with magnetism,

Faraday’s Law of Electromagnetic Induction

. So how does this work?.

When the magnet shown below is moved “towards” the coil, the pointer or needle of the Galvanometer, which is basically a very sensitive centre zero’ed moving-coil ammeter, will deflect away from its centre position in one direction only. When the magnet stops moving and is held stationary with regards to the coil the needle of the galvanometer returns back to zero as there is no physical movement of the magnetic field.

Likewise, when the magnet is moved “away” from the coil in the other direction, the needle of the galvanometer deflects in the opposite direction with regards to the first indicating a change in polarity. Then by moving the magnet back and forth towards the coil the needle of the galvanometer will deflect left or right, positive or negative, relative to the directional motion of the magnet.

Electromagnetic Induction by a Moving Magnet

Answer

Electromagnetic Induction was discovered by Michael Faraday in 1831 and James Clerk Maxwell mathematically described it as Faraday’s law of induction.

Electromagnetic Induction is a current produced because of voltage production (electromotive force) due to a changing magnetic field.

This either happens when a conductor is placed in a moving magnetic field (when using AC power source) or when a conductor is constantly moving in a stationary magnetic field.

Michael Faraday arranged a conducting wire as per the setup given below, attached to a device to measure the voltage across the circuit. When a bar magnet was moved through the coiling, the voltage detector measures the voltage in the circuit.

Electromagnetic Induction

Through his experiment, he discovered that there are certain factors that influence this voltage production. They are:

Number of Coils: The induced voltage is directly proportional to the number of turns/coils of the wire. Greater the number of turns, greater is voltage produced
Changing Magnetic Field: Changing magnetic field affects the induced voltage. This can be done by either moving the magnetic field around the conductor or moving the conductor in the magnetic field

.Applications of Electromagnetic Induction
Based on his experiments we now have Faraday’s law according to which the amount of voltage induced in a coil is proportional to the number of turns of the coil and the rate of changing magnetic field.

AC generator works on the principle of electromagnetic induction.
The working of electrical transformers are based on the electromagnetic induction.
The magnetic flow meter is based on the electromagnetic induction.
Electromagnetic Induction Formula
Mathematically, the induced voltage can be given by the following relation:

e = N × dΦ / dt
Where,

e is the induced voltage (in volts)
N is the number of turns in the coil
Φ is the magnetic flux – the amount of magnetic field at a surface (in Webbers)
t is the time (in seconds)
The significance of this discovery is a way of producing electrical energy in a circuit by using magnetic fields and not just batteries. Everyday machines like motors, generators and transformers work on the principle of electromagnetic induction

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