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Electricity and Magnetism


In this section you will learn about the big ideas of Electricity and Magnetism:

  • What is an electric field? What is its effect on charges?
  • What is the electric force affected by?
  • When charges move around a circuit, what can this be used for?
  • What do terms like 'current', 'voltage', 'resistance' and 'power' really mean?
  • What is a magnet made of?
  • How do circuits and charges interact with magnets?

  • Coulombs law and field strength

    Coulomb´s law is the electrical equivalent of Newton´s universal gravitational law. How luck we are that the universe is so simple. When defining field strength don't forget that the test charge is positive. You don't need to go inside spheres of charge

  • Magnetic fields

    Why is the North pole actually a South? Why do we define magnetic field in terms of rotation not acceleration? What is the connection between magnetic fields and electric current? Why don't magnetic waves exist without electric waves?

  • Moving charges in a magnetic field

    It's not often that you can impress your friends with your knowledge of physics but when the Northern lights appear everyone wants to know how they are formed.

  • IV graphs

     Graphs are very useful for confirming relationships but remember that resistance is the ratio of V/I not the gradient of a V vs I graph.

  • Kirchhoff's laws

     Kirchoff's laws are very useful for solving complex circuit problems but are based on simple conservation principles.

  • Parallel resistors

       Always deal with series combinations before parallel ones. Not every circuit is parallel or series but the ones in your exam will probably be.