How much work must be done to increase the speed of an electron from 0.200c to 0.210c? In (MeV)

Question

Count Iblis · Answer

The energy is given by E = gamma m c^2. Take the difference of this for v= 0.210c and 0.200 c

drwls · Answer

CountIblis is correct. gamma is 1/sqrt[1 - (v/c)^2] gamma changes from 1.0206 to 1.0461 Multiply the difference by the rest mass energy.

Andy · Answer

is rest mass energy 9.11e-31 * (3e8)^2 ?? and do I need to convert from J to ev to KeV? Thanks for the help

drwls · Answer

Yes, that is the rest mass energy in Joules. Since they do ask for the answer in MeV, use the conversion factor 1 MeV = 1.602*10^-12 J