# How much energy is required to produce the electron-positron pair ...

by vst98
Tags: electronpositron, energy, pair, produce, required
 P: 32 1. The problem statement, all variables and given/known data How much energy is required to produce the electron-positron pair in the filed of nucleus (Z=20) if electron is captured to the ground 1s state of the system. 3. The attempt at a solution I can calculate the energy of the captured electron from E = - εZ2/(2n2) where ε=me4/hbar2≈27.2eV E = - 5442eV Now I have to add this energy to the energy of created positron to have total required energy, right ? But I do not know how to find energy of a positron.
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hi vst9!
 Quote by vst98 … But I do not know how to find energy of a positron.
won't it be the same as the energy of the electron?
 P: 32 hi tiny-tim ! Yes I think so, then it is the energy and momentum conservation that places a restriction on the positron to have the same energy as electron , right ? I was a little bit confused by the "... in the filed of nucleus" part of the question, then this filed of a nucleus does not change much (except maybe the needed energy). So, the needed energy for pair creation is E=2*5442=10.88keV
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## How much energy is required to produce the electron-positron pair ...

hi vst98!

right!

i'm not sure why they mentioned the field (not "filed" ) … it doesn't seem to add anything to the rest of the question
 P: 32 Ok, thanks ! (yes it is "field" and not "filed" in the original question, my flip error :) )

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