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What do you mean by power of lens |
| Answer» The ability of a lens to converge or diverge light rays depends on its focal length. It is represented by the letter P. The SI unit of power of a lens is ‘dioptre’. It is denoted by the letter D. If f is expressed in metres, then, power is expressed in dioptres.\xa0Example : A convex lens of short focal length bends the light rays through large angles, by focussing them closer to the optical centre.\xa0Concave lens of very short focal length causes higher divergence than the one with longer focal length. The degree of convergence or divergence of light rays achieved by a lens is expressed in terms of its power. | |