Question

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 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.

Answer 1

Explanation:

It is given:

The positron has the maximum kinetic energy, $K=0.650 \mathrm{MeV}$

(a) The emission of positron and neutrino takes place simultaneously.

Therefore, Neutrino’s energy = − Given positron’s kinetic energy + 0.650

= 0.650 − 0.150

$=500 \mathrm{keV}$

(b) Neutrino has the momentum,

$P=E C$  

where, E is the neutrino’s energy, c is the light’s speed  

$\Rightarrow P=500 \times 10-193 \times 1.6 \times 108 \times 103$

$=2.67 \times 10-22 \mathrm{Kgms}-1$