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Which one of the following statements is correct about the magnification of an optical microscope?

Options

  1. AMagnification increases with the increase in focal length of eyepiece
  2. BMagnification increases with the increase in focal length of objective
  3. CMagnification does not depend upon the focal length of eyepiece
  4. DMagnification decreases with the increase in focal length of eyepiece

Correct answer

D. Magnification decreases with the increase in focal length of eyepiece

Step-by-step solution

A telescope operates with an object at infinity (or close to it), and the angular magnification is given by the ratio between objective and eyepiece focal lengths. So increasing the objective focal length increases the magnification - but it also makes the telescope tube longer, which can be awkward. So, normally, you increase magnification by switching to a shorter focal length eyepiece, not a longer focal length objective and Vice versa.

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