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:

Assertion : $A$ famous painting was painted by not using brush strokes in the usual manner,but rather a myriad of small colour dots. In this painting the colour you see at any given place on the painting changes as you move away.
Reason : The angular separation of adjacent dots changes with the distance from the painting.

The value of numerical aperture of the objective lens of a microscope is $1.25$. If light of wavelength $5000\,\mathring{A}$ is used, the minimum separation between two points, to be seen as distinct, will be....$\mu m$

$A$ 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 diameter of the objective lens of a microscope makes an angle $\beta$ at the focus of the microscope. Further,the medium between the object and the lens is an oil of refractive index $n$. Then the resolving power of the microscope

Assume that light of wavelength $6000\,\mathring{A}$ is coming from a star. What is the limit of resolution of a telescope whose objective has a diameter of $100\,\text{inch}$?