Q. The focal lengths for violet, green and red light rays are $f_{V},\ f_{G}$ and $f_{R}$ respectively. Which of the following is the true relationship
A) $f_{R} < f_{G} < f_{V}$
B) $f_{V} < f_{G} < f_{R}$
C) $f_{G} < f_{R} < f_{V}$
D) $f_{G} < f_{V} < f_{R}$
Explanation
(b) $f \propto \frac{1}{\mu - 1}$ and $\mu \propto \frac{1}{\lambda}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.