Electromagnetic Induction, History of Electromagnetic Induction (For CBSE, ICSE, IAS, NET, NRA 2022)

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Electromagnetic Induction

History of Electromagnetic Induction

  • In 1831 Micheal Farady (He Was British Scientist, Most of His Work Was in Electro-Chemistry) Gave His Famous Law Electromagnetic Induction.
  • In 1832 After Farady, Joseph Henry Who Was an American Scientist Worked on the Faraday՚s Findings and Provides Practical Uses of the Electromagnetic Induction.
  • For the First Time in August 1831, Farady Performed an Experiment for the Electromagnetic Induction.
  • For Performing His Experiment, He Takes 2 Wires and One Ring of the Iron, He Wound These 2 Wires on the Opposite Sides of the Ring. by this Arrangement, He Created Transformer like Structure.
  • At the Terminals of the First Wire, He Connected the Battery and Current Starts to Flow through It.
  • After That He Connects Galvanometer to the Other Wire Terminals, with the Deflection in the Needle of the Galvanometer He Observed That Current is Flowing in the Secondary Windings.
  • He Found That the Current in the Second Winding is Due to the Changing of Flux in It.
  • In this Method, Faraday Gives His Famous Law.

What is Electromagnetic 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.

Arrangement of an Experiment

Arrangement of an Experiment
  • 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 Voltage in the Circuit.
  • 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.

Electromagnetic Induction Formula

The induced voltage can be given by the following relation:

Where,

  • e is the induced voltage (in volts)
  • N is the number of turns in the coil
  • 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.

About the Magnitude of the Voltage Induced in the Conductor

  • If we increase the number of the turns of the conductive coil it will increase the area of the loop so the larger no of flux lines will pass through the coil and larger amount of the voltage will be induced in the loop.
  • If the speed of the coil in the field is increased than there will be larger emf will induce in the conductor.
  • If the conductive loop has constant no of turn and speed if we increase the concentration of the magnetic field then there will be more voltage induced in the coil.

Applications of Electromagnetic Induction

Based on 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.

Developed by: