#### Question

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 m s^{−1}?

Use the formula applicable to a photon.

#### Solution

Given:

Maximum kinetic energy of the positron, K = 0.650 MeV

(a) Neutrino and positron are emitted simultaneously.

∴ Energy of neutrino = 0.650 − Kinetic energy of the given positron

= 0.650 − 0.150

= 0.5 MeV = 500 keV

(b) Momentum of the neutrino, `P = E/c`

Here, E = Energy of neutrino

c = Speed of light

⇒ `P = (500 xx 1.6 xx 10^-19)/(3 xx 10^8) xx 10^3`

= `2.67 xx 10^-22 "Kgms"^-1`

Is there an error in this question or solution?

Solution In the Decay 64cu → 64ni + 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 Concept: Mass-Energy Relation and Mass Defect.