A gamma ray photon creates an electron-positron pair (pair creation). If the rest mass energy of an electron is 0.5 MeV and the total KE of electron-positron pair is 0.78 MeV, then the energy of the γ-ray photon must be

Question

A gamma ray photon creates an electron-positron pair (pair creation). If the rest mass energy of an electron is 0.5 MeV and the total KE of 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

Tardigrade Admin · Accepted Answer

Energy of &gamma;-ray photon = KE of electron positron pair + Mass energy =0.78+0.5 × 2( text an e- text and e+ text are created ) =1.78 MeV

Q. A gamma ray photon creates an electron-positron pair (pair creation). If the rest mass energy of an electron is $0.5 M e V$ and the total $K E$ of electron-positron pair is $0.78 M e V$ , then the energy of the $γ$ -ray photon must be

0.78 MeV

1.78 MeV

1.28 MeV

0.28 MeV

Energy of $γ$ -ray photon
$= K E$ of electron positron pair + Mass energy
$= 0.78 + 0.5 \times 2 (an e^{-} and e^{+} are created)$
$= 1.78 M e V$

Q. A gamma ray photon creates an electron-positron pair (pair creation). If the rest mass energy of an electron is 0.5MeV and the total KE of electron-positron pair is 0.78MeV, then the energy of the γ-ray photon must be