A compound microscope has objective focal length 2 cm, eyepiece focal length 4 cm, tube length 40 cm and least distance of distinct vision 25 cm. Find its magnifying power in normal adjustment.
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Question

A compound microscope has objective focal length 2 cm, eyepiece focal length 4 cm, tube length 40 cm and least distance of distinct vision 25 cm. Find its magnifying power in normal adjustment.

G1 Physics · Accepted Answer

Step 1: For normal adjustment, the final image is at infinity. Approximate microscope magnification: M = (L/fₒ)(D/fₑ). Step 2: Given L = 40 cm, fₒ = 2 cm, fₑ = 4 cm, D = 25 cm. Step 3: M = (40/2) × (25/4) = 20 × 6.25 = 125. Final answer: Magnifying power = 125, Option B.