Explain the similarities and differences between gravitational fields and electric fields.

AQA A-Level Physics (7408) — 3.7.1 Fields · Explain · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (5 marks)

Both gravitational and electric fields are regions where a force acts on an object.

Gravitational fields act on objects that have mass, whereas electric fields act on objects that have charge.

Gravitational forces are always attractive, while electric forces can be either attractive or repulsive.

Both fields can act at a distance and are therefore non‑contact forces.

Both fields can be represented by field lines that show the direction and relative strength of the field – the closer the lines, the stronger the field.

Examiner tips

  • Use the word ‘act’ to link the field to the force; mention mass vs charge; state attraction/repulsion; note non‑contact; describe field lines and density.

Common mistakes

  • Confusing mass with charge; forgetting that gravity is always attractive; omitting that electric forces can be repulsive; not mentioning field lines or their density.

Mark scheme (5 marks)

  1. Both gravitational and electric fields are regions where a force acts on an object
  2. Gravitational fields act on objects with mass / electric fields act on charged objects
  3. Gravitational forces are always attractive, whereas electric forces can be attractive or repulsive
  4. Both fields can act at a distance / both are non-contact forces
  5. Both fields can be represented by field lines showing the direction and strength of the field (closer lines = stronger field)

Key terms in this question

gravitational field · electric field

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