A neutral atom undergoes K-electron capture. The parent atomic mass exceeds the daughter atomic mass by 0.0020 u. Neglect electron-binding energies and nuclear recoil. Take 1 u·c² = 931.5 MeV. The neutrino energy is approximately:
Options

Question

A neutral atom undergoes K-electron capture. The parent atomic mass exceeds the daughter atomic mass by 0.0020 u. Neglect electron-binding energies and nuclear recoil. Take 1 u·c² = 931.5 MeV. The neutrino energy is approximately:

Options

G1 Physics · Accepted Answer

For electron capture using neutral atomic masses, and neglecting atomic binding corrections, Q = [M(parent)−M(daughter)]c². Thus, Q = 0.0020×931.5 = 1.863 MeV. If nuclear recoil is neglected, nearly all this energy is carried by the emitted neutrino. Therefore, E(ν) ≈ 1.86 MeV. Correct option: C.