Question

The magnifying power of a compound microscope is high if

• A. both the objective and the eyepiece has short focal lengths
• B. both the objective and the eyepiece have long focal lengths
• C. the objective has a short focal length and the eyepiece has a long focal length
• D. the objective has a long focal length and the eyepiece has a short focal length

Answer 1

Answer: (A)

The magnitying power is given by $M=\frac{L}{f_o}\frac{D}{f_e}$
for $(D>>6)$
where $L$: distance between objective and eyepiece
$D$: Least distance of distinct vision
$f_o$: Focal length of objective
$f_e$: Focal length of eyepiece