Moving a conductor relative to a magnetic field, or changing the field through a coil, induces potential difference. An induced current flows only if there is a complete circuit. Faster change, a stronger magnet or more coil turns can increase induced p.d.; direction depends on the change, and induced current produces a field opposing it. Example: Explain why induction resists the original change. The induced current’s field opposes the motion or field change causing it. Consider the conditions.