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6 Magnetism and electromagnetism

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  1. Magnetism and electromagnetism units

    1. 6.1

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

  2. (b) Magnetism

    1. 6.2Magnetic attraction and repulsion

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

    2. 6.3Hard and soft magnetic materials

      Describe the properties of magnetically hard and soft materials

    3. 6.4Magnetic field lines

      Understand the term 'magnetic field line'

    4. 6.5Induced magnetism

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

    5. 6.6Magnetic field practical

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

    6. 6.7Uniform magnetic fields

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

  3. (c) Electromagnetism

    1. 6.8Current and magnetic fields

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

    2. 6.9PElectromagnets

      Describe the construction of electromagnets

    3. 6.10PMagnetic field patterns

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

    4. 6.11PCharged particles in magnetic fields

      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

    5. 6.12Motor effect applications

      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

    6. 6.13Left-hand rule

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

    7. 6.14Changing magnetic force

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

  4. (d) Electromagnetic induction

    1. 6.15Induced voltage

      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

    2. 6.16Generating electricity

      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

    3. 6.17PTransformers

      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

    4. 6.18PStep-up and step-down transformers

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

    5. 6.19PTransformer turns ratio

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

    6. 6.20PTransformer power equation

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