Question

Wavelength of light used in an optical instrument are ${\lambda }_1=4000\dot{A}$ and ${\lambda }_2=5000\dot{A}$ then ratio of their respective resolving power is

• A. 16:25
• B. 25: 16
• C. 4 : 5
• D. 5 : 4

Answer 1

The correct option is D

5 : 4

Resolving power $\propto \frac{1}{\lambda }$
$\frac{R{P}_1}{R{P}_2}=\frac{{\lambda }_2}{{\lambda }_1}=\frac{5000}{4000}$
$R{P}_1:R{P}_2=5:4$