Question

The limit of resolution of an oil immersion objective microscope of numerical aperture $0.8$ for light of wavelength $0.6\, \mu m$ is

• A. $\frac{1.5}{8} \mu m$
• B. $\frac{3}{8} \mu m$
• C. $\frac{5}{8} \mu m$
• D. $\frac{7}{8} \mu m$

Answer 1

Answer: (A)

Numerical aperture, $N A=0.8$
Wavelength,
$\lambda=0.6\, \mu m$
$\therefore $ Limit of resolution
$=\frac{\lambda}{2 N A}=\frac{0.6}{2 \times 0.8}=\frac{0.3}{0.8}=\frac{3}{8} \mu m$