# Homework Help: Electron and Neutrino

1. Jan 11, 2010

### Minus1

One of the unstable isotopes of caesium undergoes beta decay, as a result of which it turns into an isotope of Barium, with the simultaneous emission of an electron and a neutrino. The Caesium isotope is 1.18 Mev/c^2 more massive than the Barium isotope.

Assuming that the initial and final isotopes are produced at rest , how much kinetic energy is carried of by the electron and neutrino? Explain why this must be equal to
T+cp
where T is the kinetic energy of the electron and p is the magnitude of its momentum

Use the result to determine the value of T

I have No idea at all what to do so any help at all would be greatly appreciated

(rest mass of electron=0.511Mev/c^2 and neutrino assume massless)

2. Jan 11, 2010

### diazona

Do you know the expression for the total energy of a relativistic particle? (You should)

Add up the energies of the barium atom, the electron, and the neutrino. The sum should be equal to the energy of the cesium atom. You will also need to apply conservation of momentum.