When the object is self-luminous,the resolving power of a microscope is given by the expression

What minimum separation between two objects a human eye would be able to resolve, if the eye pupil diameter is $2 \,mm$ and the two objects are $20 \,m$ away from the eye (in $\,mm$)?
(Assume, human eye to be equivalent to a convex lens and consider the average wavelength of light as $600 \,nm$.)

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

The headlights of a jeep are $1.2 \,m$ apart. If the pupil of the eye of an observer has a diameter of $2 \,mm$ and light of wavelength $5896 \,\text{Å}$ is used, what should be the maximum distance of the jeep from the observer if the two headlights are just separated?

Explain the resolving power of optical instruments and explain the resolving power of telescopes.

Wavelengths of light used in an optical instrument are $\lambda_1 = 4000 \; \mathring{A}$ and $\lambda_2 = 5000 \; \mathring{A}$. The ratio of their respective resolving powers (corresponding to $\lambda_1$ and $\lambda_2$) is: