A 12× microscope is to be built from 2.0× and 4.0× magnifying lenses. Which arrangement and tube length are correct?
Options

Question

A 12× microscope is to be built from 2.0× and 4.0× magnifying lenses. Which arrangement and tube length are correct?

G1 Physics · Accepted Answer

For a compound microscope, choose the higher-power (shorter focal length) lens as the objective, so 4.0× is the objective and 2.0× is the eyepiece. Using the lens powers with the required total magnification gives tube length 37.5 cm. Hence option A.