# Conversion from eV to J

1. Dec 20, 2011

### Peter G.

Hi,

I know that the definition of eV is the energy gained by one electron accelerated through one volt: (E = Vq)

And I therefore believe we can define the Joule as the energy gained by one coulomb of charge accelerated through one volt.

To convert eV to joules, all we would have to do is convert the charge of an electron to coulomb?

Thanks,
Peter G.

2. Dec 20, 2011

### Staff: Mentor

The eV is defined to be the energy gained by an object with a charge equal to one fundamental charge (which happens to be the charge on an electron or proton) falling through a potential difference of one volt. The joule has its own independent definition.

One eV is thus e- x 1V = (1.602 x 10-19C) x (1 J/C) = 1.602 x 10-19J

This then is your conversion factor for eV to joules.

3. Dec 21, 2011

### technician

'And I therefore believe we can define the Joule as the energy gained by one coulomb of charge accelerated through one volt.'
The relationship you have identified here is absolutely correct but the statement is used to define what is meant by 1VOLT rather than what is meant by 1 JOULE
1 VOLT = 1 JOULE per COULOMB