Year 13
Side B4: Magnetic Fields and Induction
Develop magnetic forces, induction, particle accelerators, and transformers.
Part of Year 13 CIE Physics 9702.
Topic Overview
What students will cover
This topic develops magnetic fields from force models into electromagnetic induction. You will use field-line diagrams, force rules, practical measurements, charged-particle motion, Hall probes, magnetic flux, and induction laws.
Keep the direction conventions clear. Many mistakes in this topic come from using the right equation with the wrong geometry, angle, or sign.
Revision
Topic revision route
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Recall vocabulary
magnetic field
A definition has not been added for this term yet. Use the lesson sequence below to review where it appears.
Magnetic flux density
the force acting per unit current per unit length on a wire placed at right angles to the magnetic field.
Fleming's left-hand rule
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Hall voltage
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Magnetic flux
magnetic flux density multiplied by the cross-sectional area perpendicular to the field.
flux linkage
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Faraday's law
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Lenz's law
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eddy current
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field lines
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F = BIL sin theta
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magnetic force
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current
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wire length
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gradient
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moving charge
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F = BQv sin theta
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centripetal force
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Resource bank
- Lesson resources
- 8
- Topic resources
- 0
Open the relevant lesson first, then use its linked slides, worksheets, simulations, or practice tasks.
Syllabus CIE 9702 coverage in this topic
19 points across 10 lessons
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CIE 9702 coverage in this topic
19 points across 10 lessons
20.1.1
understand that a magnetic field is an example of a field of force produced either by moving charges or by permanent magnets
20.1.2
represent a magnetic field by field lines
20.2.1
understand that a force might act on a current-carrying conductor placed in a magnetic field
20.2.2
recall and use the equation F = BIL sin θ, with directions as interpreted by Fleming’s left-hand rule
20.2.3
define magnetic flux density as the force acting per unit current per unit length on a wire placed at right‑angles to the magnetic field
20.3.1
determine the direction of the force on a charge moving in a magnetic field
20.3.2
recall and use F = BQv sin θ
20.3.3
understand the origin of the Hall voltage and derive and use the expression VH = BI / (ntq), where t = thickness
20.3.4
understand the use of a Hall probe to measure magnetic flux density
20.3.5
describe the motion of a charged particle moving in a uniform magnetic field perpendicular to the direction of motion of the particle
20.3.6
explain how electric and magnetic fields can be used in velocity selection
20.4.1
sketch magnetic field patterns due to the currents in a long straight wire, a flat circular coil and a long solenoid
20.4.2
understand that the magnetic field due to the current in a solenoid is increased by a ferrous core
20.4.3
explain the origin of the forces between current-carrying conductors and determine the direction of the forces
20.5.1
define magnetic flux as the product of the magnetic flux density and the cross-sectional area perpendicular to the direction of the magnetic flux density
20.5.2
recall and use Φ = BA
20.5.3
understand and use the concept of magnetic flux linkage
20.5.4
understand and explain experiments that demonstrate: • that a changing magnetic flux can induce an e.m.f. in a circuit • that the induced e.m.f. is in such a direction as to oppose the change producing it • the factors affecting the magnitude of the induced e.m.f.
20.5.5
recall and use Faraday’s and Lenz’s laws of electromagnetic induction
Lessons
Lesson sequence
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Lesson
01F = BIL
Introduce the magnetic force on a current-carrying conductor.
Lesson
02F = BIL Practical
Apply the magnetic force equation through practical work.
Lesson
03Particle Accelerators
Study magnetic fields through the context of particle accelerators.
Lesson
04Hall Probes
Use Hall probes to measure and interpret magnetic fields.
Lesson
05EM Induction
Introduce electromagnetic induction and the conditions needed to induce an emf.
Lesson
06EM Induction + Lenz's Law
Extend induction work using Lenz's law to determine direction.
Lesson
07Transformers & Eddy currents
Apply electromagnetic induction to transformers, eddy currents, and magnetic-field applications.
Lesson
08Revision
Review magnetic fields and induction before assessment.
Lesson
09Test
Assess understanding of magnetic fields and induction.
Lesson
10Review
Review the topic after the test and consolidate remaining weak areas.