Question

Find the limit of resolution of a microscope where the numerical aperture of the objective is 1.4 and the beam of light has a wavelength of 400 nm:

• A. 175 nm
• B. 199 nm
• C. 224 nm
• D. 240 nm

Hint:

Higher numerical aperture and shorter wavelengths reduce the limit of resolution, enhancing a microscope’s resolving power.

Answer 1

The Correct Option is A

The limit of resolution (\( d \)) is given by:

\( d = \frac{\lambda}{2 \times NA} \)

where \( \lambda = 400 \, \text{nm} \) and \( NA = 1.4 \).

Substituting the values: 

\( d = \frac{400}{2 \times 1.4} = 175 \, \text{nm}. \)