Question

What is the rest mass energy of an electron?

• A. 1 eV
• B. 0.51 MeV
• C. 931 MeV
• D. none of these

Answer 1

The correct option is B

0.51 MeV

$E=m{c}^2=9.1\times {10}^{-31}\times (3\times {10}^8{)}^2=8.2\times {10}^{-14}J=\frac{8.2\times {10}^{-14}}{1.6\times {10}^{-19}}=5.1\times {10}^{5}eV=0.51MeV$