This key facts covers The DC Motor 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 4 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 4 of 12
Practice
19 questions
Recall
12 flashcards
🔄 The DC Motor
Components:
- Coil — carries current, experiences force
- Magnets — provide magnetic field
- Split-ring commutator — reverses current every half turn
- Brushes — connect power supply to spinning coil
Why the commutator is essential:
- Without it, coil would rotate 180° then stop (or oscillate)
- Commutator reverses current direction every half turn
- This keeps the force pushing in the same rotational direction
- Result: continuous rotation
To make motor spin faster:
- Increase current
- Use stronger magnets
- Add more turns to the coil
Quick Check: A wire carries a current of 3 A in a magnetic field of flux density 0.5 T. The length of wire in the field is 0.2 m. Calculate the force on the wire.
F = B × I × L = 0.5 × 3 × 0.2 = 0.3 N. The force acts at right angles to both the current and the magnetic field direction (use Fleming's Left-Hand Rule to find its direction).
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.
Practice Questions for The Motor Effect
What is the motor effect?
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.
Quick Recall Flashcards
19 questions on The Motor Effect — practise free
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