The energy the electron gives up passing between the electrodes is equal to the product between its charge and the potential difference between the electrodes:
[tex]\Delta U = e \Delta V[/tex]
where
e is the electron charge
[tex]\Delta V[/tex] is the potential difference
Plugging numbers into the equation, we find that the electron gives up is
[tex]\Delta U = (1.6 \cdot 10^{-19} C)(14700 V)=2.35 \cdot 10^{-15} J[/tex]
