Question

If we need a magnification of 375 from a compound microscope of tube length 150 mm and an objective of focal length 5 mm, the focal length of the eye-piece, should be close to : 

(1) 22 mm 

(2) 12 mm 

(3) 33 mm 

(4) 2 mm

Answer 1

Answer is (1) 22 mm

Case-I

Case-II

If final image is at infinity

f_e = 22 mm

Comments

sir how did we get d =25

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we generally take D=25 cm

Answer 2

Answer is (1) 22 mm