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The arrangement of lenses that makes up a ``Gallilean'' compound microscope is pictured above. The focal lengths of the objective and eyepiece lenses are $f_o = 1$ cm and $f_e = -1$ cm. The tube length is $L = 20$ cm.

a) Find $s$ (the object distance from the objective lens) such that the final image viewed by the eye is in focus (at infinity, as imaged by the eyepiece).

b) Draw the ray diagram from which you can find the overall magnification. NOTE WELL the tube length goes to the second (negative) focal point of the eyepiece. Why?

c) From this diagram, find the overall magnification. Explain each part (that is, what are the separate roles of the objective and eyepiece).

d) What is the advantage of this kind of microscope compared to one with two converging lenses?