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Electromagnetic Induction

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Topics

  • Introduction
  • Faraday’s Law of Electromagnetic Induction
  • Application

Introduction:

Electromagnetic induction was discovered by Michael Faraday in 1831 and later mathematically formulated by James Clerk Maxwell as Faraday’s Law of Induction. It refers to the generation of an electric current (electromotive force or EMF) due to a changing magnetic field.

Principle of Electromagnetic Induction:

  • When a conductor is placed in a changing magnetic field, an electric current is induced in it.
  • This can occur in two ways:
    1. Moving a conductor through a stationary magnetic field.
    2. Changing the magnetic field around a stationary conductor.
  • The induced current follows Lenz’s Law, which states that the induced current opposes the change in magnetic flux.

Faraday’s Law of Electromagnetic Induction

Faraday’s Law of Induction states that whenever the magnetic flux passing through a coil changes, an induced current is generated in the coil. This happens in the following cases:

  • When the current in the solenoid is switched ON or OFF, the magnetic field changes, inducing a current in the nearby coil.
  • When the current in the solenoid increases or decreases, the changing magnetic field induces a current in the coil.
  • When the coil is moved laterally or away from the solenoid, the number of magnetic field lines passing through it changes, inducing a current.

This phenomenon proves that a changing magnetic field creates an electromotive force (EMF) in a conductor, leading to the flow of induced current.

The amount of induced voltage (EMF) is proportional to:

  • The number of turns (N) in the coil.
  • The rate of change of magnetic flux (Φ) over time (t).

Mathematical Formula:

`e = N × "dΦ"/"dt"`

Where:

  • e = Induced voltage (volts)
  • N = Number of turns in the coil
  • Φ = Magnetic flux (Webers)
  • t = Time (seconds)

Factors Affecting Electromagnetic Induction

  1. Number of Turns in the Coil: More turns result in a higher induced voltage.
  2. Rate of Change of Magnetic Field: Faster changes induce a higher voltage.
  3. Strength of the Magnetic Field: A stronger magnetic field produces a greater induced current.

Application:

  1. AC generators convert mechanical energy into electrical energy.
  2. Transformers transfer electrical energy between circuits at different voltages.
  3. Induction cooktops generate heat using electromagnetic currents.
  4. Electric guitars and microphones convert sound waves into electrical signals.
  5. Magnetic flow meters measure the flow rate of conductive fluids.
  6. Wireless charging systems transfer power without physical contact.
  7. Eddy current brakes slow down moving vehicles using electromagnetic resistance.
  8. MRI scanners use induction to create detailed body images in medical diagnostics.
  9. Smart cards and RFID systems store and transfer data wirelessly.
  10. Induction motors are used in household appliances and industrial machines.
If you would like to contribute notes or other learning material, please submit them using the button below.

Video Tutorials

We have provided more than 1 series of video tutorials for some topics to help you get a better understanding of the topic.

Series 1


Series 2


Shaalaa.com | Electromagnetic Induction Part 9

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