JEE Main & Advanced
Physics
Nuclear Physics And Radioactivity
Question Bank
Nucleus, Nuclear Reaction
question_answer
A gamma ray photon creates an electron- positron pair. If the rest mass energy of an electron is 0.5 MeV and the total K.E. of the electron- positron pair is 0.78 MeV, then the energy of the gamma ray photon must be [MP PMT 1991]
A) 0.78 MeV
B) 1.78 MeV
C) 1.28 MeV
D) 0.28 MeV
Correct Answer:
B
Solution :
Energy of g-ray photon =\[0.5+0.5+0.78=1.78\ MeV\].