Exam-style question
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In the alternator-output trace scenario, a rotating coil output is compared with a direct-current supply. Which option best applies the AQA A-Level Physics objective to explain inverse-square behaviour for point charges. while avoiding calling alternating emf steady direct potential difference?.
- A.field-case-46: Apply Explain inverse-square behaviour for point charges. within Coulomb's law.
- B.field-case-46: Treat Coulomb's law as separate from Electric fields, so the measured field idea is not used.
- C.field-case-46: Choose a memorised equation without checking direction, sign, field geometry or units.
- D.field-case-46: Replace the A-Level fields reasoning with a broad GCSE label only.
Model answer
What a good answer should say
- The correct option is field-case-46: Apply Explain inverse-square behaviour for point charges.
- within Coulomb's law.
Explanation
Why this works
It is correct because it keeps the reasoning inside Coulomb's law and answers the approved learning objective: Explain inverse-square behaviour for point charges. The other options are weaker because they switch to the wrong fields concept, ignore the measured quantity, lose direction or sign information, or use a generic statement instead of A-Level Physics reasoning.
Common mistake
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