Electromagnetism

Students should be able to:

1. draw the pattern of the magnetic field due to currents in straight wires and in solenoids and state the effect on the magnetic field of changing the magnitude and/or direction of the current
2. describe the application of the magnetic effect of a current in electromagnets (e.g. circuit breakers)
3. describe experiments to show the force on a current-carrying conductor, and on a beam of charged particles, in a magnetic field, including the effect of reversing
   1. the current
   2. the direction of the field
4. deduce the relative directions of force, field and current when any two of these quantities are at right angles to each other using Fleming’s left-hand rule
5. explain how a current-carrying coil in a magnetic field (e.g. in a motor) experiences a turning effect and that the effect is increased by increasing
   1. the number of turns on the coil
   2. the current
6. describe the action of a split-ring commutator in a two-pole, single-coil motor and the effect of winding the coil on to a soft-iron cylinder.