Learn about and revise lenses and their power, real and virtual images, and ray diagrams with GCSE Bitesize Physics.

Lens ray diagram. Magnification; ... eg a light ray changes direction when refracted by a lens. occurs at the air ... (concave) lenses are used in spectacles for distance viewing.

Question1: A ray of light travelling in air enters obliquely into water. ... Therefore, the object is placed 30 cm in front of the concave lens. Ray diagram: ...