Question

what is ment by power of a lens write its SI unit A student uses a lens of focal length 40 cm and another of -20 cm write the nature and power of each lens

Answer 1

The degree of convergence or divergence of a lens is expressed aspower of the lens. It is the reciprocal of the focal length of the lens taken in metres. Its S.I. unit is Dioptre( D ). 1 Dioptre is defined as the power of a lens whose focal length is 1 m.....


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Answer 2

power of lens means the convergence or divergence of the lens. itz si unit is diapter . the positive focal length means the lens used is convex while negative indicates that the lens used is concave