NDA 2020 Physics question

Physics Ray Optics and Optical Instruments NDA 2020

A lens has a power of +2·0 Dioptre. Which one of the following statements about the lens is true ?

(A)The lens is concave and has a focal length of 0·5 metre
(B)The lens is convex and has a focal length of 2·0 metre
(C)The lens is convex and has a focal length of 0·5 metreCorrect
(D)The lens is concave and has a focal length of 2·0 metre

Answer: (C)

Solution

A positive power means a converging (convex) lens. Its focal length is m.

Question ID VK-031683