Answer the following question:

Why must both the objective and the eyepiece of a compound microscope have short focal lengths?


A compound microscope produces an angular magnification of [(25/fe) + 1]


where,


fe = focal length of the eyepiece


It can be inferred that if fe is small, then angular magnification of the eyepiece will be large.


The angular magnification of the objective lens of a compound microscope is given as


1/(|u0|f0)


Where, uo = object distance for the objective lens


fo = focal length of the objective


The magnification is large when uo > fo. In the case of a microscope, the object is kept close to the objective lens. Hence, the object distance is very little. Since, uo is small, fo will be even smaller. Therefore, fe and fo are both small in the given condition.


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