The separation between two microscopic particles is measured as $P_A$ and $P_B$ by two different lights of wavelength $2000 \; \mathring{A}$ and $3000 \; \mathring{A}$ respectively. Then:

Two points separated by a distance of $0.1\,mm$ can just be resolved in a microscope when a light of wavelength $6000\ \mathring{A}$ is used. If the light of wavelength $4800\ \mathring{A}$ is used,this limit of resolution becomes.......$mm$.

Explain the resolving power of a microscope.

$A$ telescope of diameter $2 \ m$ uses light of wavelength $5000 \ \mathring{A}$ for viewing stars. The minimum angular separation between two stars whose image is just resolved by this telescope is

The human eye has an approximate angular resolution of $\theta = 5.8 \times 10^{-4} \text{ rad}$ and a typical photo printer prints a minimum of $300 \text{ dpi}$ (dots per inch, $1 \text{ inch} = 2.54 \text{ cm}$). At what minimal distance $d$ should a printed page be held so that one does not see the individual dots (in $\text{ cm}$)?

The numerical aperture of a microscope is $0.12$, and the wavelength of light used is $600 \, nm$. Then its limit of resolution will be nearly $............. \, \mu m$.