When a positronium atom (electron + positron) decays, it emits two photons. What are the energies of the photons?
A)0.511 MeV and 1.022 MeV
B)0.225 MeV and 1.022 MeV
C)0.225 MeV and 0.285 MeV
D)0.256 MeV and 0.256 MeV
E)0.511 MeV and 0.511 MeV

Question

Quizplus · Accepted Answer

The total energy of the positronium atom is the sum of the rest mass energies of the electron and positron, each 0.511 MeV. When it decays, it emits two photons, each with energy equal to the rest mass energy of the electron or positron, which is 0.511 MeV.

When a Positronium Atom (Electron + Positron) Decays, It Emits