A solenoid is used in an electric door lock. When there is a current in the solenoid, the magnetic field lines outside it run from end X to end Y. The current is then reversed and kept the same size.
Which statement describes the magnetic field after the current is reversed?
Outside the solenoid, the field lines now leave from both ends.
Outside the solenoid, the field lines still run from end X to end Y, but inside they reverse.
Outside the solenoid, the field lines now run from end Y to end X.
Outside the solenoid, the field lines still run from end X to end Y.
90 exam-style questions on AQA GCSE Physics 7.2 The motor effect, covering 7.2.1 Electromagnetism, 7.2.2 Fleming's left-hand rule (HT only), 7.2.3 Electric motors (HT only), and 7.2.4 Loudspeakers (HT only). Each one has a worked solution and a mark scheme showing where the marks go.