Physics GCSE
principal focus
What principal focus means in Physics GCSE, as defined for AQA.
Definition of principal focus
Check what you remember
Read the wording for your board, then hide it and explain principal focus in your own words. Rough notes are fine. This is a self-check, with no mark or grade.
Reference: AQA
The point on the axis beyond the lens where parallel rays of light are brought to a focus.
Topics that use principal focus
- Lenses (physics only) (AQA GCSE)
Related terms
- always virtual
- arrowheads in or out
- converging and diverging
- diverging lens
- dotted projections
- magnifying glass
- matched comparison
- real image
Using principal focus in the exam
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