# I De-Broglie Wavelength of a captured electron?

1. Feb 9, 2018

### Sritika

For a proton to capture an electron to form a neutron and a neutrino (assumed massless), the
electron must have some minimum energy. For such an electron,how can the de-Broglie wavelength be found out?

2. Feb 9, 2018

### Staff: Mentor

Calculate the electron energy, calculate its momentum, calculate its de Broglie wavelength.

Is this a homework question?

3. Feb 9, 2018

### Sritika

Nope.I just came across this question.It kind of intrigued me.With such a minimal information,how can you find out the wavelength?

4. Feb 9, 2018

### Staff: Mentor

With the steps I described.
Conservation of energy and a few basic kinematic equations.

5. Feb 11, 2018

### Staff: Mentor

Hint: under what circumstances does a neutron + neutrino have the smallest possible energy?

(to a very good approximation, at least)

6. Feb 13, 2018

### Sritika

When is this $e p \rightarrow n \nu_e$ possible?