MCQ
The magnifying power of a compound microscope increases when
  • A
    The focal length of objective lens is increased and that of eye lens is decreased
  • B
    The focal length of eye lens is increased and that of objective lens is decreased
  • C
    Focal lengths of both objective and eye-piece are increased
  • Focal lengths of both objective and eye-piece are decreased

Answer

Correct option: D.
Focal lengths of both objective and eye-piece are decreased
d
( d)$m \propto \frac{1}{{{f_o}{f_e}}}$

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