Q. 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
A) $0.78\ MeV$
B) $1.78\ MeV$
C) $1.28\ MeV$
D) $0.28\ MeV$
Explanation
(b) Energy of $\gamma$-ray photon $= 0.5 + 0.5 + 0.78 = 1.78MeV$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.