JEE Main & Advanced Physics Atomic Physics JEE PYQ-Atomic Physics

  • question_answer
    The energy required to remove the electron from a singly ionized Helium atom is 2.2 times the energy required to remove an electron from Helium atom. The total energy required to ionize the Helium atom completely is [JEE Online 15-04-2018]

    A) \[20eV\]

    B) \[79eV\]

    C) \[109eV\]

    D) \[34eV\]

    Correct Answer: B

    Solution :

    [b] Let
    \[{{E}_{1}}=\]energy required to remove
    \[{{e}^{-}}\]
    from singly ionised Helium atom
    \[=\frac{+13.6{{z}^{2}}}{{{n}^{2}}}\]
    \[=\frac{(13.6){{(2)}^{2}}}{{{(1)}^{2}}}\]
    \[=54.4eV\]
    \[{{E}_{2}}=\] Energy required to remove an \[{{e}^{-}}\] from He –atom
    Given \[{{E}_{1}}=2.2{{E}_{2}}\]
    \[\therefore {{E}_{2}}=\frac{{{E}_{1}}}{2.2}=\frac{54.4}{2.2}=24.7eV\]
    \[\therefore \] Energy required to remove both  \[{{e}^{-}}'s\] from He-atom
    \[=24.7+54.4\]
    \[=79.1eV\]


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