An electron has a rest energy of 0.511 MeV. At what speed would its kinetic energy equal 1.022 MeV?
A) 0.866 c
B) 0.943 c
C) 0.888 c
D) 0.971 c
E) 0.500 c

Question

Quizplus · Accepted Answer

First, we need to find the kinetic energy of the electron: 
KE = 1.022 MeV - 0.511 MeV = 0.511 MeV

Then, we can use the relativistic kinetic energy equation: 
KE = (gamma - 1) * mc^2

where gamma is the Lorentz factor and m is the rest mass of the electron.

Substituting the values, we get: 
0.511 MeV = (gamma - 1) * 0.511 MeV

Solving for gamma: 
gamma = 2

Now, we can use the equation for Lorentz factor: 
gamma = 1 / sqrt(1 - v^2/c^2)

Solving for v: 
v = 0.943 c

Therefore, the answer is B.

An Electron Has a Rest Energy of 0