Electromagnetism

Electromagnetism

1. Magnetic Fields

   • Region of space where magnetic forces can be felt
   • Magnetic Field Lines
     • Indicates the direction a 'magnetic north' would travel in a magnetic field if free to do so
     • Connect the north and south pole of a magnet

2. Magnetic Flux Density (B)

   • Strength of the magnetic field
   • Vector quantity
   • Tesla

3. Forces in a magnetic field

   • Force on a current-carrying conductor in a magnetic field
     • F = IlB
       • F = force
       • I = current
       • l = length
       • B = magnetic flux density
     • When the flow of current in the conductor is perpendicular to the magnetic field
     • Direction
       • Fleming's left hand rule
   • Force on a charged particle moving through a magnetic field
     • F = qvB
       • q = charge
       • v = velocity
       • B = magnetic flux density
   • Forces between currents
     • Definition of the Ampere is based on this principle

4. Electromagnetic Induction

   • Faraday's Law
     • Magnitude of the induced emf is proportional to the rate of change of magnetic flux linking a circuit
   • Magnetic flux (Φ)
     • Φ = BA
       • B = magnetic flux density
       • A = area
     • Vector quantity
     • Weber (Wb)
   • Lenz's Law
     • Direction of the induced emf always opposes the charge causing it
   • Mutual Induction
     • Transformer
   • Self-induction
     • Inductor