JEE Main & Advanced Sample Paper JEE Main Sample Paper-26

  • question_answer
    For compound microscope\[{{f}_{0}}=1\,cm\], \[{{f}_{e}}=2.5\,cm\]. An object is placed at distance \[1.2\,cm\] from object lens. What should be length of microscope for normal adjustment?

    A)  \[8.5\] cm                                

    B)  \[8.3\] cm

    C)  \[6.5\] cm                                

    D)  \[6.3\]cm

    Correct Answer: B

    Solution :

    When final image formed at normal adjustment, then length of compound microscopic. \[L={{v}_{0}}+{{v}_{0}}\,\,\,\,=\frac{{{u}_{0}}{{f}_{0}}}{({{u}_{0}}+{{f}_{0}})}\,+\frac{{{f}_{e}}D}{{{f}_{e}}+D}\] \[=\frac{-1.2\times 1}{1.2+1}\,=\frac{2.5\,\times 25}{2.5+25}\] \[=6+2.27\,=8.27\,\approx \,8.3\]


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