Question
Question: A gamma ray photon creates an electron-positron pair. If the rest mass energy of an electron is 0.5 ...
A gamma ray photon creates an electron-positron pair. If the rest mass energy of an electron is 0.5 MeV and the total kinetic energy of the electron-positron pair is 0.78 MeV, then the energy of the gamma ray photon must be
A
0.78 MeV
B
1.78 MeV
C
1.28 MeV
D
0.28 MeV
Answer
1.78 MeV
Explanation
Solution
Energy of γ-rays photon = 0.5 + 0.5 +0.78 = 1.78 MeV