The aperture diameter of a telescope is $5 \mathrm{m}$ . The separation between the moon and the earth is $4\times {10}^5 \mathrm{k}\mathrm{m}$ . With light of wavelength of $5893 \mathrm{\AA }$ , the minimum separation between objects on the surface of moon, so that they are just resolved, is close to:

_________microscope will have maximum resolving power.

A microscope will have maximum resolving power if it is used to illuminate the specimen with,

Assertion: Oil immersion objective microscope is used to achieve high resolving power.
Reason: Resolving power of the microscope increases with the increase in refractive index.