CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2001

  • question_answer
    The ionisation potential of hydrogen is \[13.6\text{ }eV.\] Then the energy released when an electron jumps from \[n=3\]to \[n=2\]orbit, is:

    A)  \[2.89\,eV\]                     

    B) \[1.89\,eV\]

    C)  \[3.89\,eV\]                     

    D) \[4.89\,eV\]

    Correct Answer: B

    Solution :

    The energy of electron in nth orbit of H-atom is \[{{E}_{n}}=-\frac{Rhc}{{{n}^{2}}}\] Given ionization potential \[=13.6\,eV\]                 So, ionization energy                                 \[Rhc=13.6\,eV\]                             So,          \[{{E}_{n}}=-\frac{13.6}{{{n}^{2}}}eV\]                 In \[n=2\]orbit                 \[{{E}_{2}}=-\frac{13.6}{4}=-3.4\,eV\] In \[n=3\]orbit \[{{E}_{3}}=-\frac{13.6}{{{3}^{2}}}\] \[=-\frac{13.6}{9}=1.51\,eV\] Energy released is \[\Delta \Epsilon ={{\Epsilon }_{3}}-{{E}_{2}}\] \[=-1.51\,eV-(-3.4\,eV)\] \[=-1.5\,eV+3.4\,eV\] \[=1.89\,eV\]


You need to login to perform this action.
You will be redirected in 3 sec spinner