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JCECE Engineering JCECE Engineering Solved Paper-2009

  • question_answer
    A beam of light of wavelength \[600\,\,nm\] from a distant source falls on a single slit \[1\,\,mm\] wide and the resulting diffraction pattern is observed on a screen \[2\,\,m\] away. The distance between the first dark fringes on either side of the central bright fringe is

    A) \[1.2\,\,cm\]                     

    B) \[1.2\,\,mm\]

    C) \[2.4\,\,cm\]                     

    D) \[2.4\,\,mm\]

    Correct Answer: D

    Solution :

    \[\beta =\frac{\lambda D}{d}=\frac{600\times {{10}^{-19}}}{1\times {{10}^{-3}}}=12\times {{10}^{-4}}m\] So, distance between the first dark fringes on either side of the central bright fringe                 \[X=2\beta \]                 \[=2\times 12\times {{10}^{-4}}m\]                 \[=24\times {{10}^{-4}}m\]                 \[=2.4\,\,mm\]


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