JEE Main & Advanced Physics Nuclear Physics And Radioactivity Question Bank Nucleus, Nuclear Reaction

  • question_answer
    The rest energy of an electron is [MP PMT 1996; BCECE 2003]

    A)            510 KeV                                  

    B)            931 KeV

    C)            510 MeV                                

    D)            931 MeV

    Correct Answer: A

    Solution :

                       Rest energy of an electron \[{{r}_{n}}\propto {{n}^{2}}\]                    Here \[{{m}_{e}}=9.1\times {{10}^{-31}}kg\]and c = velocity of light                    \[\therefore \]Rest energy \[=9.1\times {{10}^{-31}}\times {{(3\times {{10}^{8}})}^{2}}joule\]                    \[=\frac{9.1\times {{10}^{-31}}\times {{(3\times {{10}^{8}})}^{2}}}{1.6\times {{10}^{-19}}}eV=510\ keV\]


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