(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I need to build a telescope from two magnifying lens, one is 2x the other is 5x. First I need to give the total magnification possible, state which lens to use as the objective and finally to state the length of the telescope.

2. Relevant equations

l Ml = Fo/Fe total magnification is lM1l x lM2l Length = Focal length of objective + focal length of eyepiece

3. The attempt at a solutionThe total possible magnification is 10X. I use the 2X for the objective because you need a long focal length and smaller magnification. I am stuck on how to get the length of the scope. I know the absolute value of M and can say that Fobjective is equal to lMl times F of eyepiece. But I don't have either focal length as far as I can tell and so I have no way to determine the length. I have the answer, so I know it should be 55 cm but why????? Any help would be much appreciated. Frostking

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# Building a telescope

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