What is meant by the power of a lens? What is its S.I. unit? Name the type of lens whose power is positive. The image of an object formed by a lens is real, inverted and of the same size as theobject. If the image is at a distance of 40 cm from the lens, what is the nature and power of the lens? Draw ray diagram tojustify your answer.

What is meant by the power of a lens? What is its S.I. unit? Name the

1.	What is meant by the power of a lens? What is its S.I. unit? Name the type of lens whose power is positive. The image of an object formed by a lens is real, inverted and of the same size as theobject. If the image is at a distance of 40 cm from the lens, what is the nature and power of the lens? Draw ray diagram tojustify your answer.
Answer» Solution :(i) Power of LENS- (ii) S.I. UNIT is DIOPTRE. (III)Convex lens has positive power. (iv) `v=+40 cm, h.=h` The lens is real inverted and of same size `:.` object is at 2F `2f=40: f=20cm`