Generating Electricity (Edexcel GCSE Physics)

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The Generator Effect

Higher Tier Only

  • Electromagnetic (EM) induction is used to generate electricity
  • EM induction is when:

A voltage is induced in a conductor or a coil when it moves through a magnetic field or when a magnetic field changes through it

  • This is done by the conductor or coil cutting through the magnetic field lines of the magnetic field
  • This is often referred to as the generator effect and is the opposite to the motor effect
    • In the motor effect, there is already a current in the conductor which experiences a force
    • In the generator effect, there is no initial current in the conductor but one is induced (created) when it moves through a magnetic field

Generator Effect in the Laboratory

  • A potential difference will be induced in the conductor if there is relative movement between the conductor and the magnetic field
  • Moving the electrical conductor in a fixed magnetic field
    • When a conductor (such as a wire) is moved through a magnetic field, the wire cuts through the fields lines
    • This induces a potential difference in the wire

Moving an electrical conductor in a magnetic field to induce a potential difference

  • Moving the magnetic field relative to a fixed conductor
    • As the magnet moved through the coil, the field lines cut through the turns on the coil
    • This induces a potential difference in the coil

coil-induction, IGCSE & GCSE Physics revision notes

When the magnet enters the coil, the field lines cut through the turns, inducing a potential difference

  • A sensitive voltmeter can be used to measure the size of the induced potential difference
  • If the conductor is part of a complete circuit then a current is induced in the conductor
    • This can be detected by an ammeter

Generator Effect in the Large-Scale Generation of Electrical Energy

  • EM Induction can be used to generate electricity on a large scale by replacing the moving wire with a spinning coil
  • An a.c (alternating current) generator looks very similar to a motor, but instead of connecting it to a power supply, a coil is spun to produce electricity
  • As the coil rotates, it cuts through the field lines
  • This induces a potential difference between the end of the coil, which also then creates a current
  • The electricity produce is in the form of a.c which can be found in the mains supply of a building
  • This is also called an alternator

AC generator, downloadable AS & A Level Physics revision notes

A.C Generator

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Ashika

Author: Ashika

Expertise: Physics Project Lead

Ashika graduated with a first-class Physics degree from Manchester University and, having worked as a software engineer, focused on Physics education, creating engaging content to help students across all levels. Now an experienced GCSE and A Level Physics and Maths tutor, Ashika helps to grow and improve our Physics resources.