Loading…
Loading…
GCSE Physics · key term
A lens that is thinner in the middle and makes parallel rays diverge as though they came from a principal focus.
Used by AQA and OCR
Specification 4.6.2.5 · Paper 2
A lens that spreads rays travelling parallel to its principal axis apart.
Revise: LensesA concave lens makes parallel rays spread out; after leaving it, they appear to have come from the focus on the near side.
Specification P5.3c · Paper 2 (Foundation), Paper 4 (Higher)
A lens that is thinner in the middle than at its edges and makes parallel rays diverge.
Revise: Ray diagrams and lensesA concave lens is thinner in the middle. Parallel rays spread away from the principal axis, so it is a diverging lens. Their dashed backward extensions meet at the principal focus on the same side as the incoming light.
Paper 1, Paper 2
Revise: Reflection, Refraction and LensesBoth convex and concave lens diagrams use the principal axis, optical centre, foci and straight rays; their main difference is whether they bring parallel rays together or spread them apart.
Remember the correction pairings: a concave lens corrects short-sightedness; a convex lens corrects long-sightedness.
Distinguish the lens shapes and actions: a convex lens converges parallel rays, whereas a concave lens diverges them.
Create a free account to read GCSE Physics revision notes for your exam board and track your progress.