Magnetism and electromagnetism

Topics

Choose a topic to revise

Sample objectives

What this unit covers

• Permanent and induced magnetism, magnetic forces and fields: State that the poles of a magnet are the places where magnetic forces are strongest.
• Permanent and induced magnetism, magnetic forces and fields: Describe how two magnets exert forces on each other when brought close together.
• Permanent and induced magnetism, magnetic forces and fields: Describe how magnetic field strength depends on distance from the magnet.
• Permanent and induced magnetism, magnetic forces and fields: State that magnetic field lines go from the north-seeking pole to the south-seeking pole of a magnet.
• The motor effect: Describe how the strength of the magnetic field around a wire depends on current through the wire.
• The motor effect: Describe the magnetic field around a solenoid as having a similar shape to that of a bar magnet.
• The motor effect: (HT only) Describe the motor effect as the force on a current-carrying conductor placed in a magnetic field.
• The motor effect: (HT only) State that the magnet producing the field and the conductor exert a force on each other.
• The motor effect: (HT only) Describe rotation of a current-carrying coil in a magnetic field as the basis of an electric motor.
• The motor effect: (HT only) Use motor-effect reasoning to explain the operation of a simple electric motor.
• The motor effect: (Physics only) (HT only) State that loudspeakers and headphones use the motor effect.
• The motor effect: (Physics only) (HT only) Describe how variations in current in an electrical circuit are converted into pressure variations in sound waves.
• Induced potential, transformers and the National Grid (physics only) (HT only): (Physics only) (HT only) Describe how a potential difference is induced across a conductor when the conductor moves relative to a magnetic field.
• Induced potential, transformers and the National Grid (physics only) (HT only): (Physics only) (HT only) Describe how a potential difference is induced when there is a change in the magnetic field around a conductor.
• Induced potential, transformers and the National Grid (physics only) (HT only): (Physics only) (HT only) State that the generator effect is used in an alternator to generate alternating current.
• Induced potential, transformers and the National Grid (physics only) (HT only): (Physics only) (HT only) Explain how the generator effect is used in a dynamo to generate dc.
• Induced potential, transformers and the National Grid (physics only) (HT only): (Physics only) (HT only) State that microphones use the generator effect.
• Induced potential, transformers and the National Grid (physics only) (HT only): (Physics only) (HT only) Link movement of a coil in a magnetic field to induced potential difference in a microphone.
• Induced potential, transformers and the National Grid (physics only) (HT only): (Physics only) (HT only) Recognise that knowledge of laminations and eddy currents in the core is not required.
• Induced potential, transformers and the National Grid (physics only) (HT only): (Physics only) (HT only) State that iron is used in the core because it is easily magnetised.