MagnetismHigher Tier

Higher Tier: Force Calculation and Direction

Part of The Motor Effect · GCSE GCSE Physics revision

This higher tier covers Higher Tier: Force Calculation and Direction within The Motor Effect for GCSE Physics. Revise The Motor Effect in Magnetism for GCSE Physics with 19 exam-style questions and 12 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 9 of 12 in this topic. This section is most useful once the core foundation idea is secure, because it adds the detail that pushes answers higher.

Topic position

Section 9 of 12

Practice

19 questions

Recall

12 flashcards

🎓 Higher Tier: Force Calculation and Direction

The force on a current-carrying conductor is given by F = BIL:

F = force in Newtons (N)
B = magnetic flux density in Tesla (T)
I = current in Amperes (A)
L = length of conductor in the field in metres (m)

This formula assumes the conductor is perpendicular to the field. If the conductor is at an angle θ to the field, the force becomes F = BIL sin(θ) — maximum at 90°, zero at 0°.

Worked example: A horizontal wire carrying 5 A lies in a vertical magnetic field of 0.4 T. The wire is 0.3 m long. Find the force: F = 0.4 × 5 × 0.3 = 0.6 N. Direction found using left-hand rule.

Motor torque: In a real motor, two sides of the coil experience equal but opposite forces — creating a turning effect (torque). More turns = more wire in the field = larger force = larger torque = faster or more powerful motor.

Keep building this topic

Read this section alongside the surrounding pages in The Motor Effect. That gives you the full topic sequence instead of a single isolated revision point.

Memory Aid Exam Focus Making Things Move with Electricity The Motor Effect

Practice Questions for The Motor Effect

What is the motor effect?

A. A force experienced by a current-carrying conductor placed in a magnetic field
B. The generation of a voltage when a conductor moves through a magnetic field
C. The heating of a wire when a large current flows through it
D. The attraction between two permanent magnets

1 markfoundation

Explain how Fleming's left-hand rule is used to find the direction of the force on a current-carrying conductor in a magnetic field.

2 marksstandard

Quick Recall Flashcards

Left hand: thumb =?

Motion/Force

Fleming's Left Hand: for?

Motors (force on current-carrying conductor)

19 questions on The Motor Effect — practise free

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