What is the rest energy of an electron, given its mass is $9.11 \times 10^{-31} \textrm{ kg}? Give your answer in joules and MeV.

Video Transcript

This is College Physics Answers with Shaun Dychko. The rest energy of an electron is its mass times c squared. That's 9.11 times 10 to the minus 31 kilograms times 2.998 times 10 to the 8 meters per second squared giving 8.19 times 10 to the minus 14 joules. We can express that energy in electron volts by multiplying the joules by 1 electron volt for every 1.602 times 10 to the minus 19 joules and the joules cancel giving us 511 kiloelectron volts, is another way to express that same energy.