Q. A man with defective eyes cannot see distinctly object at the distance more than $60\ cm$ from his eyes. The power of the lens to be used will be
A) $+ 60\ D$
B) $- 60\ D$
C) $- 1.66\ D$
D) $\frac{1}{1.66}D$
Explanation
(c) $f = - d = - 60\ cm$
$\therefore P = \frac{100}{f} = - \frac{100}{60} = - \frac{10}{6} = - 1.66\ D$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.