• Tags: microscope, magnification, optical-instruments
• Difficulty: Moderate

A simple microscope is a single convex lens used to view objects closer than the least distance of distinct vision (D = 25 cm).

When final image is at the near point (D): M = 1 + D/f. This gives maximum magnification.

When final image is at infinity (relaxed eye): M = $\frac{D}{f}$. This is more comfortable for prolonged viewing.

The object must be placed between F and the optical centre of the lens. The image formed is virtual, erect, and magnified.