Permanent and induced magnetism, magnetic forces and fields

    AQA
    GCSE

    Magnetism originates from the alignment of domains within ferromagnetic materials, creating regions of influence known as magnetic fields where non-contact forces act. Permanent magnets generate their own persistent fields, whereas induced magnets develop temporary magnetism only when exposed to an external field, a process that invariably results in a force of attraction. The density of magnetic field lines indicates the magnetic flux density, representing the strength of the field, which diminishes with distance from the poles. Candidates must distinguish between the behavior of soft and hard magnetic materials and apply these principles to terrestrial magnetism and navigation.

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    Objectives
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    Exam Tips
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    Pitfalls
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    Key Terms
    4
    Mark Points

    What You Need to Demonstrate

    Key skills and knowledge for this topic

    • Award 1 mark for drawing magnetic field lines that are continuous, do not cross, and emerge from the North pole to enter the South pole
    • Credit responses that state induced magnetism is always attractive, regardless of the pole of the permanent magnet presented
    • Award 1 mark for linking the density (closeness) of field lines directly to the strength of the magnetic field
    • Candidates must state that a plotting compass contains a small bar magnet that aligns with the Earth's magnetic field

    Marking Points

    Key points examiners look for in your answers

    • Award 1 mark for drawing magnetic field lines that are continuous, do not cross, and emerge from the North pole to enter the South pole
    • Credit responses that state induced magnetism is always attractive, regardless of the pole of the permanent magnet presented
    • Award 1 mark for linking the density (closeness) of field lines directly to the strength of the magnetic field
    • Candidates must state that a plotting compass contains a small bar magnet that aligns with the Earth's magnetic field

    Examiner Tips

    Expert advice for maximising your marks

    • 💡When drawing field lines, ensure they exit and enter the magnet perpendicular to the surface; careless sketching loses marks
    • 💡Always describe the force between an induced magnet and a permanent magnet as 'attraction'—never 'repulsion'
    • 💡Use the phrase 'non-contact force' when defining the interaction between separated magnets to gain specific technical credit

    Common Mistakes

    Pitfalls to avoid in your exam answers

    • Drawing magnetic field lines that cross or touch, which is physically impossible and results in zero marks for that section
    • Indicating the direction of the magnetic field arrows from South to North (must be North to South)
    • Stating that induced magnets can repel a permanent magnet; candidates must understand induced magnetism results only in attraction
    • Confusing the geographic North Pole with the magnetic north pole; the Earth's magnetic north is physically a magnetic south pole

    Key Terminology

    Essential terms to know

    Likely Command Words

    How questions on this topic are typically asked

    Draw
    Describe
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    Compare
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    Practical Links

    Related required practicals

    • •{"code":"Standard Investigation","title":"Plotting Magnetic Fields","relevance":"Technique using a plotting compass to map field lines around a bar magnet"}

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