Question

A thin converging lens of focal length 5cm is used as a simple microscope. Calculate its magnifying power when image formed lies at:

1. Infinity.
2. Least distance of distinct vision (D = 25 cm).

Answer 1

(a) At infinity,

M = `"D"/"f"`

M = `(25  "cm")/(5  "cm")`

M = 5

(b) At least distance of distinct vision

M = 1 + `"D"/"f"`

M = 1 + 5

M = 6