Compound Microscope: A compound microscope has a 18-cm-long barrel and an objective lens with a focal length of 8.0 mm. What is the focal length of the eyepiece to give a total magnification of 240? It is adjusted for minimum eyestrain for persons with a near point of 25 cm.
A. 1.3 m
B. 1.5 cm
C. 1.9 cm
D. 2.1 cm
E. 2.3 cm
Answer: D
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