Question

What is meant by the magnifying power of a simple microscope?

Answer 1

The magnifying power (or angular magnification) of a simple microscope is defined as the ratio of the visual angle subtended by the image to the visual angle subtended by the object, when both are placed at the least distance of distinct vision (D).

Formula:

M = `"Visual angle by the image at distance D"/"Visual angle by the object at distance D"`

Or M = `1 + D/f`

where f is the focal length of the convex lens and D is the least distance of distinct vision (25 cm).

Hence, magnifying power of the lens is reciprocal to the focal length of the lens. However, magnifying power cannot be increased indefinitely.