Question

the magnifying power of simple microscope is 2 cm then find the focal length of simple microscope

Answer 1

magnifying power M =2
focal length f =?
when the image is form at the near point,
then,D=25cm
M=1+D/f
D/f=1-M
f=D/1-M
f=25/(1-2)
f=25cm
when the image is form at infinity ,
Magnification M=D/f
f=D/M
f=25/2
f=12.5cm