In the decay 64 Cu → 64 Ni + e + + v, the maximum kinetic energy carried by the positron is found to be 0.650 MeV. (a) What is the energy of the neutrino which was emitted together with a positron of kinetic energy 0.150 MeV? (b) What is the momentum of this neutrino in kg ms –1 ? Use the formula applicable to a photon.

Question

Philoid · Accepted Answer

a) Maximum energy of positron refers to zero K.E of the neutrino

So when the energy of positron is 0.150 MeV as energy is conserved,

Energy of neutrino

b) For a photon,

, where c = speed of light

Energy of neutrino in SI = 0.500 × 10⁶ × 1.6 × 10^-19 J

Momentum kgms^-1

= 2.67 × 10^-22 kgms^-1