Q. Wavelength of light used in an optical instrument are $\lambda_{1} = 4000\ \mathring{\mathrm{A}}\ and\ \ \lambda_{2} = 5000\mathring{\mathrm{A}},$ then ratio of their respective resolving powers (corresponding to $\lambda_{1}$ and $\lambda_{2}$) is

A) 16 : 25
B) 9 : 1
C) 4 : 5
D) 5 : 4
Explanation

(d) Resolving power of an optical instrument is inversely proportional to $\lambda\ i.e.,\ RP \propto \frac{1}{\lambda}\ $
$\therefore\frac{Resolving\ power\ at\ \lambda_{1}}{Resolving\ power\ at\ \lambda_{2}} = \frac{\lambda_{2}}{\lambda_{1}} = \frac{5000}{4000} = 5:4$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.