Question

A photon materializes into an electron-positron pair. The kinetic energy of the electron is found to be 0.19 MeV. What was the energy of the photon?

(a) 0.38 MeV

(b) 0.70 MeV

(c) 1.40 MeV

(d)

Answer 1

Correct option: (c) 1.40 MeV

Explanation:

Conservation of Energy,

We know that rest mass energy of e+ + e- is .5 MeV

Hence Ep = .5 + .5 + .19 x 2 = 1.40 MeV