The aperture diameter of a telescope is $5\; m$. The separation between the moon and the earth is $4 \times 10^{5} \; km$. With light of wavelength $5500\; \mathring{A}$, the minimum separation between objects on the surface of the moon, so that they are just resolved, is close to......$m$.

If the red light is replaced by blue light illuminating the object in a microscope, the resolving power of the microscope:

$A$ telescope is used to observe two objects at a distance of $z = 10 \ km$ which are $s = 0.12 \ m$ apart and illuminated by light of wavelength $\lambda = 600 \ nm$. Estimate the diameter of the objective lens of the telescope if it can just resolve the two objects. Assume diameter $D >> \lambda$ and separation between objects $s << z$. The answer is in $cm$.

The resolving power of a telescope depends on

The distance of the moon from earth is $3.8 \times 10^5 \text{ km}$. The eye is most sensitive to light of wavelength $5500 \text{ Å}$. The separation of two points on the moon that can be resolved by a $500 \text{ cm}$ telescope will be......$m$.

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