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Introduction to Electromagnetic Induction

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Estimated time: 9 minutes
CBSE: Class 12
Maharashtra State Board: Class 10
CISCE: Class 12

Introduction

  • Electricity and magnetism were considered separate and unrelated phenomena for a long time.
  • In the early nineteenth century, scientists such as Oersted and Ampere established that electricity and magnetism are related. They found that moving electric charges produce magnetic fields.
  • For example, an electric current flowing through a conductor can deflect a magnetic compass needle placed near it.
  • Around 1830, Michael Faraday in England and Joseph Henry in the USA showed that an electric current can be induced in a closed coil when it is exposed to a changing magnetic field.
CBSE: Class 12
Maharashtra State Board: Class 10
CISCE: Class 12

Definition: Electromagnetic Induction

The phenomenon in which electric current is generated in a conductor or closed coil due to a varying magnetic field is called electromagnetic induction.

CBSE: Class 12
CISCE: Class 12

Electromagnetic Induction

A current is produced when:

  • A magnet moves relative to a coil
  • A coil moves in the magnetic field of a magnet
  • The magnetic field around a stationary conductor changes
  • The current in a nearby solenoid coil is switched on or off
  • The current in a nearby solenoid coil is increased or decreased
CBSE: Class 12
Maharashtra State Board: Class 10
CISCE: Class 12

Faraday’s Experiment

  • Faraday showed in 1831 that a moving magnet can produce an electric current in a conductor.
  • When a magnet moves towards or away from a coil, a small current is produced in the coil.
  • The current produced in the coil is called induced current.
CBSE: Class 12
Maharashtra State Board: Class 10
CISCE: Class 12

Faraday’s Law of Induction

Faraday’s experiments showed that current is induced in a coil whenever the number of magnetic field lines passing through the coil changes.

This may happen when:

  • A magnet moves towards or away from a coil
  • A coil is moved in front of a solenoid
  • Current in a solenoid is switched on or switched off
  • Current in a solenoid is increased or decreased

Therefore: Whenever the number of magnetic field lines passing through a coil changes, a current is induced in the coil.

This statement is known as Faraday’s Law of Induction.

CBSE: Class 12
Maharashtra State Board: Class 10
CISCE: Class 12

Key Terms

Term Meaning
Electromagnetic induction Production of electric current due to a changing magnetic field
Induced current Current produced in a coil due to electromagnetic induction
Coil A conductor wound into loops
Solenoid A long coil of wire that produces a magnetic field when current flows through it
Changing magnetic field A magnetic field whose strength or effect through a coil changes
CISCE: Class 12

Significance

Electromagnetic induction is not only a theoretical concept. It has important practical uses in daily life and modern technology.

The principle of electromagnetic induction is used in:

  • Electric generators
  • Transformers
  • Induction motors
  • Wireless chargers

Without electromagnetic induction, modern civilisation would not have electric lights, trains, telephones, personal computers, or communication networks.

Faraday's and Henry's experiments led to the development of generators and transformers, which are important for producing and using electricity.

CBSE: Class 12
Maharashtra State Board: Class 10
CISCE: Class 12

Key Points: Introduction to Electromagnetic Induction

  • Electricity and magnetism are interrelated.
  • Electric current can produce a magnetic field.
  • A changing magnetic field can produce electric current.
  • The production of electric current by a varying magnetic field is called electromagnetic induction.
  • Michael Faraday showed in 1831 that a moving magnet can produce current in a conductor.
  • The current produced due to electromagnetic induction is called induced current.
  • Generators, transformers, induction motors, and wireless chargers work on electromagnetic induction.

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.

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