NEET AIPMT SOLVED PAPER SCREENING 2005

  • question_answer
                    The total energy of an electron in the first excited state of hydrogen is about -3.4 eV. Its kinetic energy in this state is:

    A)                                                                                                                                                                            -3.4eV            

    B)                 -6.8eV  

    C)                 6.8 eV 

    D)                 3.4 Ev

    Correct Answer: D

    Solution :

                    Key Idea: The kinetic energy is equal to the negative of total energy.                 Kinetic energy of electron                 \[K=\frac{Z{{e}^{2}}}{8\pi {{\varepsilon }_{0}}r}\]                 Potential energy of electron                 \[U=-\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Z{{e}^{2}}}{r}\]                         \[\therefore \]            Total energy                 \[E=K+U=\frac{Z{{e}^{2}}}{8\pi {{\varepsilon }_{0}}r}-\frac{Z{{e}^{2}}}{4\pi {{\varepsilon }_{0}}r}\]                         \[orE=-\frac{Z{{e}^{2}}}{8\pi {{\varepsilon }_{0}}r}\]                         \[orE=-K\]                         \[orK=-E=-\,(-3.4)=3.4\,eV\]


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