Q. In an eye-piece, field lens and eye lens have focal lengths $7.5\ cm$ and $7.3\ cm$. To eliminate spherical aberration, distance between them would be
A) $0.2\ cm$
B) $0.4\ cm$
C) $0.1\ cm$
D) $0.5\ cm$
Explanation
(a) $d = f_{1} - f_{2} = 7.5 - 7.3 = 0.2\ cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.