Define visual angle. 

In a compound microscope, the intermediate image is

Draw the ray diagram for formation of image in a simple microscope.

Draw a labelled diagram of simple microscope and establish an expression for the magnifying power of simple microscope, when the image formed at 

$\left(\mathrm{i}\right)$ Infinity

Given below are two statements : one is labeled as Assertion $A$ and the other is labeled as Reason $R$.

Assertion $A$: For a simple microscope, the angular size of the object equals the angular size of the image.

Reason $R$: Magnification is achieved as the small object can be kept much closer to the eye than $25 \mathrm{cm}$ and hence it subtends a large angle. In the light of the above statements, choose the most appropriate answer from the options given below: