Concave Mirror:- EDUCATIONAL EQUIPMENT » PHYSICS EQUIPMENTS » Concave Mirror Concave Mirror – Physics Optical Equipment A concave mirror, or converging mirror, has a reflecting surface that bulges inward (away from the incident light). Concave mirrors reflect light inward to one focal point. They are used to focus light. Mirrors are highly slivered, optically true (spray painted at the back) with a beautiful ring on its outer surface). Diameter Focal length 50mm 10-100cm 75mm 10-100cm