The minimum energy that a photon must have to create an electron-positron pair is
A) 0.511 MeV.
B) 1.022 MeV.
C) 2.044 MeV.
D) 0.256 MeV.
E) any amount more than zero.

Question

Quizplus · Accepted Answer

To create an electron-positron pair, the photon energy must be converted into the mass of the particles (according to E=mc^2). Each particle has a rest mass of 0.511 MeV/c^2, so the total energy required is twice this amount, or 1.022 MeV. Therefore, choice B is the correct answer.

The Minimum Energy That a Photon Must Have to Create