VIT Engineering VIT Engineering Solved Paper-2015

  • question_answer
    A compound microscope having magnifying      power 35 with its eye-piece of focal length       10 cm. Assume that the final image is at least      distance of distinct vision then the      magnification produced by the objective is

    A) -4                                           

    B) 5     

    C) 10                                          

    D) -10

    Correct Answer: D

    Solution :

    For a compound microscope the magnifying power is given by                   \[\alpha ={{\omega }^{2}}\theta \] When the final image is at least distance of distance vision then                 \[\Rightarrow \] So,             \[{{\omega }^{2}}=\frac{2qE}{mL}\] \[T=\frac{2\pi }{\omega }=2\pi \sqrt{\frac{mL}{2qE}}\]            \[\frac{T}{4}.\] \[\text{t=}\frac{\text{T}}{\text{4}}\text{=}\frac{\text{ }\!\!\pi\!\!\text{ }}{\text{2}}\sqrt{\frac{\text{mL}}{\text{2qE}}}\]            \[\text{250Jk}{{\text{g}}^{\text{-1}}}{{\text{K}}^{\text{-1}}}\] \[\Delta \theta =0.4K\]            \[\text{U=}\frac{\text{1}}{\text{2}}\text{C}{{\text{V}}^{\text{2}}}\] The negative sign indicates that the image formed by objective is inverted.


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