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For the telescope is in normal adjustment (i.e., when the final image is at infinity)? what is the separation between the objective lens and the eyepiece?

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#### Solution

Focal length of the objective lens, f_{o} = 140 cm

Focal length of the eyepiece, f_{e} = 5 cm

In normal adjustment, the separation between the objective lens and the eyepiece = f_{o} + f_{e} = 140 + 5 = 145 cm

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