JEE Main & Advanced Sample Paper JEE Main - Mock Test - 45

  • question_answer
    The de Broglie wavelength of an electron in the ground state of hydrogen atom is : \[[K.E.=13.6\,eV=1.602\times {{10}^{-19}}J]\]

    A) \[33.28\text{ }nm\]

    B) \[3.328\text{ }nm\]

    C) \[0.3328\text{ }nm\]

    D)        \[0.0332\text{ }nm\]

    Correct Answer: C

    Solution :

    For electron in the ground state, \[m\text{vr=}\frac{h}{2\pi }\Rightarrow m\text{v=}\frac{h}{2\pi r}\] Now, \[m\text{v=}\frac{h}{\lambda }\] So, \[\frac{h}{\lambda }=\frac{h}{2\pi r}\Rightarrow \lambda =2\pi r\] \[\lambda =2\times 3.14\times 0.53\overset{o}{\mathop{A}}\,=3.328\overset{o}{\mathop{A}}\,\] \[=3.328\times {{10}^{-10}}m\] \[=0.3328\times {{10}^{-9}}m=0.3328nm\]


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