A) 0.36 MeV
B) 0.41 MeV
C) 0.48 MeV
D) 1.32 MeV
Correct Answer: A
Solution :
Rest mass energy of electron = 0.54 MeV i.e., \[{{m}_{0}}\,\,{{c}^{2}}=0.54\,\] MeV ... (i) But the kinetic energy of electron \[=m{{c}^{2}}-{{m}_{0}}{{c}^{2}}\] ... (ii) Also, \[m=\frac{{{m}_{0}}}{\sqrt{1-\frac{{{v}^{2}}}{{{c}^{2}}}}}\] \[=\frac{{{m}_{0}}}{\sqrt{1-{{(0.8)}^{2}}}}=\frac{{{m}_{0}}}{0.6}\] So, \[m{{c}^{2}}=\frac{{{m}_{0}}{{c}^{2}}}{0.6}\] \[=\frac{0.54}{0.6}\]MeV (From Eq (i)) \[m{{c}^{2}}=0.9\] MeV ... (ii) Substituting values of Eq (ii) and (i) in Eq (ii)we get KE = (0.9 - 0.54) MeV = 0.36 MeV
You need to login to perform this action.
You will be redirected in
3 sec
