Chapter 18
Electromagnetism
A current produces a magnetic field and can experience a force in another magnetic field.
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Magnetic fields from currents
Draw straight-wire and solenoid fields, then predict the effects of changing or reversing current.
Using electromagnets
Connect a controlled current and an iron core to lifting and a magnetic overcurrent trip.
Magnetic force and its direction
Use experiments and current/field directions to explain forces on a wire and a charged-particle beam.
Why a current-carrying coil turns
Find the forces on the two active sides and explain how current and turn count affect turning.
The single-coil d.c. motor
Trace the coil connections, half-turn current reversal and role of the soft-iron cylinder.