Light Questions - nature of light, reflection, colour etc - GCSE Level
Reflection, formation of shadows and colour used to be tested at KS3 in SATs.
Now these examinations are no longer compulsory the questions are examined in GCSE papers.
Most are of a similar standard to what you may be asked at KS4
... and for harder 'O Level' standard questions on light - see here
Questions on 'optics' - lenses etc are here there are lots of them!