Define lens. What is difference between convex and concave lens?
Lens: A transparent medium bound by two surfaces, of which one or both surfaces are spherical, forms a lens: Convex lens: A lens having two spherical surfaces, bulging outwards is called a double convex lens or convex lens. It is thicker at the middle as compared to the edges. Convex lens converges light. Hence, convex lens are called converging lens. Concave lens: A double concave lens is bounded by two spherical surfaces curved inwards. It is thicker at edges than in the middle. Concave lens is diverging in nature.
