The focal length of objective and eye-piece of a microscope are ${\rm{1}}\,\,{\rm{cm }}\,{\rm{and}}\,{\rm{ 5}}\,\,{\rm{cm}}$ respectively. If the magnifying power for relaxed eye is $45$, then length of the tube is

JEE PHYSICS MCQ: RAY OPTICS

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The focal length of objective and eye-piece of a microscope are

\mathrm{1}\,\,\mathrm{cm }\,\mathrm{and}\,\mathrm{ 5}\,\,\mathrm{cm}

respectively. If the magnifying power for relaxed eye is

45

, then length of the tube is

View answer and explanation

Correct option: B

\mathrm{15}\,\,\mathrm{cm}

Option B (

\mathrm{15}\,\mathrm{cm}

) is correct because the length of the tube is calculated by summing the image distance of the objective lens and the focal length of the eyepiece for a relaxed eye.

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