Q. A person cannot see distinctly at the distance less than one metre. Calculate the power of the lens that he should use to read a book at a distance of $25\ cm$
A) $+ 3.0\ D$
B) $+ 0.125\ D$
C) $- 3.0\ D$
D) $+ 4.0\ D$
Explanation
(a) $P = \frac{1}{f} = - \frac{1}{v} + \frac{1}{u} = - \frac{1}{100} + \frac{1}{25} = \frac{3}{100} = + 3\ D$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.