H2 Physics 9478 · Topic 15
Electromagnetic forces: currents, fields and beams
Keep field production, conductor force and moving-charge force distinct, apply direction rules with charge sign, and compare electric and magnetic beam deflection before balancing crossed fields.
Before you begin
Study each reviewed objective cluster, then use the recorded diagnostic and repair plan. H2 practice evidence remains separate from H1 and H3.
Be comfortable with: Current Electricity objective chainD.C. Circuits objective chainElectric Fields objective chain
How the ideas connect
- Magnetic fields produced by currents
- Conductor force, flux density, current balance and parallel currents
- Force on a moving charge
- Charged-particle beams in uniform fields
- Velocity selection in crossed fields
Learn in order
Lesson route
Objective clusters
- 01Magnetic fields produced by currents 17(a)–(d)Learn and apply 4 reviewed syllabus outcomes in one coherent cluster.
- 02Conductor force, flux density, current balance and parallel currents 17(e)–(i)Learn and apply 5 reviewed syllabus outcomes in one coherent cluster.
- 03Force on a moving charge 17(j)–(k)Learn and apply 2 reviewed syllabus outcomes in one coherent cluster.
- 04Charged-particle beams in uniform fields 17(l)Learn and apply 1 reviewed syllabus outcomes in one coherent cluster.
- 05Velocity selection in crossed fields 17(m)Learn and apply 1 reviewed syllabus outcomes in one coherent cluster.
Prove your understanding
Practice and repair
Key ideas and reference
Use this concise Electromagnetic forces: currents, fields and beams checklist to locate the right objective cluster. Full definitions, derivations and worked examples stay in the linked lessons.
- Keep field production, conductor force and moving-charge force distinct, apply direction rules with charge sign, and compare electric and magnetic beam deflection before balancing crossed fields.
- Magnetic fields produced by currents 17(a)–(d)
- Conductor force, flux density, current balance and parallel currents 17(e)–(i)
- Force on a moving charge 17(j)–(k)
- Charged-particle beams in uniform fields 17(l)
- Velocity selection in crossed fields 17(m)
Course coverage and review details
Topic 17 states no explicit exclusions. Straight-wire, flat-coil and long-solenoid field equations use their named ideal geometries; a ferrous core changes the air-core model. In F = BIl sin θ, θ is between conventional current and B; in F = BQv sin θ, direction is determined for positive charge then reversed for negative charge. Magnetic force does no work. Circular-path formulae require velocity perpendicular to a uniform B. Velocity selection requires uniform mutually perpendicular E, B and beam velocity with opposing forces.
Coverage is reviewed against 9478 topic 17(a)–(m), PDF page 26. Selected-response progress does not by itself prove constructed, diagrammatic or practical performance.
Reviewed 2026-08-01