Electric and magnetic fields

An electric field is created by a change in voltage (charge). The higher the voltage the stronger the field.

A magnetic field is created when electric current flows. The greater the current the stronger the magnetic field.

  • A change in an electric field induces a change in the magnetic field.
  • A change in a magnetic field induces a change in the electric field.
  • An electromagnetic wave is the result of the interaction of electric and magnetic fields.
  • An electromagnetic wave can be propagated when either the charge of an electric field changes or when the current of a magnetic field changes.
  • When changes in electric and magnetic fields result in electromagnetic waves, they produce synchronised oscillations that travel at right angles to one another.
  • The velocity at which electromagnetic waves propagate in a vacuum is the speed of light which is 300,000 kilometres per second.
  • Once an electromagnetic wave propagates outward it cannot be deflected by an external electric or magnetic field.
  • The reason an electromagnetic wave does not need a medium to propagate through is because the only thing that is waving/oscillating is the value of the electric and magnetic fields.