NEET Physics Nuclei Questions Solved


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

(b) Energy of γ-ray photon = 0.5+0.5+0.78 = 1.78 MeV 

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