6 Magnetism and electromagnetism

Use the following units: ampere (A), volt (V) and watt (W)

Know that magnets repel and attract other magnets and attract magnetic substances

Describe the properties of magnetically hard and soft materials

Understand the term 'magnetic field line'

Know that magnetism is induced in some materials when they are placed in a magnetic field

Practical: investigate the magnetic field pattern for a permanent bar magnet and between two bar magnets

Describe how to use two permanent magnets to produce a uniform magnetic field pattern

Know that an electric current in a conductor produces a magnetic field around it

Describe the construction of electromagnets

Draw magnetic field patterns for a straight wire, a flat circular coil and a solenoid when each is carrying a current

Know that there is a force on a charged particle when it moves in a magnetic field as long as its motion is not parallel to the field

Understand why a force is exerted on a current-carrying wire in a magnetic field and how this effect is applied in simple d.c. electric motors and loudspeakers

Use the left-hand rule to predict the direction of the resulting force when a wire carries a current perpendicular to a magnetic field

Describe how the force on a current-carrying conductor in a magnetic field changes with the magnitude and direction of the field and current

Know that a voltage is induced in a conductor or a coil when it moves through a magnetic field or when a magnetic field changes through it and describe the factors that affect the size of the induced voltage

Describe the generation of electricity by the rotation of a magnet within a coil of wire and of a coil of wire within a magnetic field, and describe the factors that affect the size of the induced voltage

Describe the structure of a transformer and understand that a transformer changes the size of an alternating voltage by having different numbers of turns on the input and output sides

Explain the use of step-up and step-down transformers in the large-scale generation and transmission of electrical energy

Know and use input voltage ÷ output voltage = primary turns ÷ secondary turns, Vₚ/Vₛ = Nₚ/Nₛ.

Know and use input power = output power, VₚIₚ = VₛIₛ, for a 100% efficient transformer.