JEE Main & Advanced Sample Paper JEE Main Sample Paper-42

  • question_answer
    The kinetic energy of an electron with de-Broglie wavelength of 0.3 nm is

    A) 0.168 eV         

    B) 16.8 eV

    C) 1.68 eV                       

    D) 2.5 Ev

    Correct Answer: B

    Solution :

    \[\lambda =\frac{h}{\sqrt{2mE}}\]\[\Rightarrow \]\[E=\frac{{{h}^{2}}}{2m{{\lambda }^{2}}}\]\[=\frac{{{(6.6\times {{10}^{-34}})}^{2}}}{2\times 9.1\times {{10}^{-31}}\times {{(0.3\times {{10}^{-9}})}^{2}}}\]\[=2.65\times {{10}^{-18}}J=16.8eV\]


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