A compound microscope has an objective of focal length mm and

PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Geometrical optics and imaging · Geometrical optics and imaging

Optics and Photonics, Ch Stops, pupils and optical instruments

Problem

A compound microscope has an objective of focal length fo=4.00f_o = 4.00 mm and, in its standard configuration, a tube length L=160L = 160 mm (measured from the objective's focal point to the eyepiece's focal point) with an eyepiece of focal length fe=25.0f_e = 25.0 mm. The overall magnification is M=−(L/fo)(d0/fe)M = -(L/f_o)(d_0/f_e) with the standard near point d0=250d_0 = 250 mm. ((a)) The eyepiece is swapped for one of focal length fe=10.0f_e = 10.0 mm, the tube length unchanged at 160160 mm. Find the new overall magnification. ((b)) Keeping this 10.010.0 mm eyepiece, the manufacturer lengthens the tube to L=200L = 200 mm. Find the overall magnification now, and state in words how MM scales with LL for fixed objective and eyepiece.

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