Chapter 33, Problem 79P

(III) Given two 12-cm-focal-length lenses, you attempt to make a crude microscope using them. While holding these lenses a distance 55 cm apart, you position your microscope so that its objective lens is distance d_o from a small object. Assume your eye’s near point N = 25 cm. (a) For your microscope to function properly, what should d_o be? (b) Assuming your eye is relaxed when using it, what magnification M does your microscope achieve? (c) Since the length of your microscope is not much greater than the focal lengths of its lenses, the approximation M ≈ Nℓ/f_ef_o is not valid. If you apply this approximation to your microscope, what % error do you make in your microscope’s true magnification?