Video narration
Why can one mirror show your normal image, while another magnifies or shrinks it? At a bathroom mirror, light reflects: angle of incidence equals angle of reflection-the law of reflection. A plane mirror makes a virtual, upright, same-size image behind it, as far behind as you are in front. Two mirrors at an angle can reflect, creating multiple images. Key point: reflection stays the same; shape decides whether rays spread or meet. Concave mirrors bring rays together, magnifying nearby objects or focusing light. Convex mirrors spread rays, giving virtual, upright, smaller images and wider views. Cartesian convention: opposite light is negative. Mirror formula: one over f equals one over v plus one over u. For f equals minus ten and u equals minus fifteen, v equals minus thirty centimetres. Then m equals minus two: twice as large, inverted. That's why: same law; mirror shape changes where rays meet.