Dual Nature Of Light Question 112
Question: Rest mass energy of an electron is 0.51 MeV. If this electron is moving with a velocity 0.8 c (where c is velocity of light in vacuum), then kinetic energy of the electron should be.
Options:
A) 0.28 MeV
B) 0.34 MeV
C) 0.39 MeV
D) 0.46 MeV
Show Answer
Answer:
Correct Answer: B
Solution:
Given m0c2 = 0.51 MeV and v = 0.8 c K.E. of the electron = mc2? m0c2 But $ m=\frac{m_{0}}{\sqrt{1-\frac{v^{2}}{c^{2}}}}=\frac{m_{0}}{\sqrt{1-{{( \frac{0.8,c}{c} )}^{2}}}}=\frac{m_{0}}{\sqrt{0.36}}=\frac{m_{0}}{0.6} $ Now, $ mc^{2}=\frac{0.51}{0.6} $ MeV = 0.85 MeV \ K.E. = (0.85 ? 0.51)MeV = 0.34 MeV.
BETA
