Magnetic effect of a current and the d.c. motor

Learning objectives

Describe and sketch the pattern and direction of the magnetic field around a straight current-carrying wire and inside and around a solenoid, and describe experiments to demonstrate them

Describe how the magnetic field around a wire or solenoid changes when the size or direction of the current changes (Extended)

Describe how the magnetic effect of a current is used in electromagnets, relays and loudspeakers, with examples of their applications

Describe an experiment to show that a current-carrying conductor in a magnetic field experiences a force, including the effect of reversing the current or the field

Use Fleming's left-hand rule to relate the directions of force, field and current, and predict the direction of the force on a beam of charged particles moving through a magnetic field (Extended)

Know that a current-carrying coil in a magnetic field experiences a turning effect that increases with more turns, a larger current or a stronger field, and at Extended explain the operation of a simple d.c. motor including the split-ring commutator and brushes