Question

Define magnifying power if a simple microscope. How can it be increased?

Answer 1

The magnifying power of the microscope is defined as

the ratio of the angle subtended by the image at the eye to the angle subtended by the object

(assumed to be placed at the least distance of distinct vision D= 25 cm)

at the eye, i.e,
Magnifying power = $$1+ \dfrac{D}{F}$$
Where F is the focal length of the lens.
The magnifying power of a microscope can be increased by using the lens of short focal length. But it cannot be increased indefinitely.