Why does a convex lens converge and a concave lens diverge the rays of light?

Asked by Utkarsh sharma | 21st Dec, 2013, 09:39: AM

Expert Answer:

Light rays entering the front convex or concave surface of a lens are refracted (bent) by the refractive index of the lens to a new path through the lens material. As light leaves the lens material it is bent again as it re-enters the air. The extent that light rays bend depends on the lens material and the curvature of the lens surfaces.
Light entering a convex lens is refracted towards a focal point as per the laws of refraction.
Light entering a concave lens is refracted away from a focal as per the laws of refraction.
In both cases, light at the edges bends more than light passing through the centre of the lens.

Answered by  | 22nd Dec, 2013, 10:13: AM

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