In a microscope of tube length 10 cm two convex lenses are arranged with focal length of 2 cm and 5 cm. Total magnification obtained with this system for normal adjustment is 5ᵏ. The value of k i $s_____$
Options

Question

In a microscope of tube length 10 cm two convex lenses are arranged with focal length of 2 cm and 5 cm. Total magnification obtained with this system for normal adjustment is 5ᵏ. The value of k i $s_____$

Options

G1 Physics · Accepted Answer

For a compound microscope in normal adjustment, M = (ℓ/f₀)(D/fₑ). Given, ℓ = 10 cm, f₀ = 2 cm, fₑ = 5 cm, D = 25 cm. Therefore, M = (10/2)(25/5) = 5×5 = 25. The question gives M = 5ᵏ. Hence, 5ᵏ = 25 = 5². Therefore, k = 2. Correct option: A.

In a microscope of tube length 10 cm two convex lenses are arranged with focal length of 2 cm and 5 cm. Total magnification obtained with this system for normal adjustment is 5ᵏ. The value of k i s_____