Electromagnetic induction

• When a conductor (can be a wire, coil or just a piece of metal) experiences a changing magnetic field a potential difference or voltage is induced in it. The strength of the potential difference depends on the strength of the magnetic field, how fast it changes i.e. how fast the coil is spinning, and how much of the conductor is exposed to the field i.e. how many turns in the coil.
• Electricity can be generated by either moving a magnet inside a coil of wire or rotating a coil inside a permanent magnetic field.
• Model answer for a generator (Rotating coil):

  ·         Coil is rotated within a magnetic field

  ·         As it turns the coil cuts the magnetic field lines.

  ·         This induces a voltage (or current) in the coil.

  ·         This can then be connected to an existing circuit.

  ·         In a generator, energy is being converted from kinetic (mechanical) energy into electrical energy.

  ·         The size of the induced voltage (or current) can be increased by:

  ·         Using a stronger magnet

  ·         Having more turns in the coil

  ·         Spinning/moving the coil faster.
• Model answer for a generator (Rotating magnet)

  ·         Magnet is rotated within a coil

  ·         As it turns the coil cuts the constantly changing magnetic field lines from the magnet.

  ·         This induces a voltage (or current) in the coil.

  ·         This can then be connected to an existing circuit.

  ·         In a generator, energy is being converted from kinetic (mechanical) energy into electrical energy.

  ·         The size of the induced voltage (or current) can be increased by:

  ·         Using a stronger magnet

  ·         Having more turns in the coil

  ·         Spinning/moving the magnet faster.