For the simple microscope, we have: Let the focal length be f. (a) When the image is formed at D = 25 cm, the magnifying power of the simple microscope is given by m = 1 + `(D/f)` `=> 3 =1+(25/f)` `=> 25/f = 2` `=> f = 25/2 = 12.5 "cm"` (b) When the image is formed at infinity in normal adjustment, the magnifying power is given by `m = D/f = 25/12.5 =2.0` So, the magnifying power is 2 if the image is formed at infinity. |