Can someone explain the difference between Volts and Electron Volts?

[synoptic]

OK,

Bear with me, I'm a mature student returning to the sciences after a 16 year break...

I'm currently reading up on electricity and cannot, for the life of me, get my head around what 'appears' to be an inconsistency. Obviously my brain isn't 'seeing' the answer properly just yet so I could do with some help.

Basically, if one coulomb has 6.25 x 10 -18 electrons and 1 volt is the potential energy required to carry out 1 Joule of work how is it that 1 eV is only worth 1.602 x 10. -19 Joules? Why not 6.25 X 10 -18 Joules?

I've read around many sites but can't get my brain to shift into the right perspective with this...

Cheers.

 

[Azael]

A electronvolt is the kinetic energy a electron gets when its passed through a 1 volt electrostatic potential difference.

I don't quite follow why you think that amount of energy in relation to a joule should be the same as a electrons charge in relation to a coulomb??

 

[dav2008]

By the way your exponent is off. 6.25 x 10¹⁸ electrons make up one coulomb of charge.

 

[synoptic]

Ok, this is where I am going wrong obviously. The problem is I need to be un-confused...

 

[synoptic]

By the way your exponent is off. 6.25 x 10¹⁸ electrons make up one coulomb of charge.

Quite right, apologies for the typo.

 

[Physics Monkey]

A volt is one joule/coulomb. The charge of an electron is - 1.6 x 10^-19 coulombs. The energy acquired by one electron being accelerated through a potential difference of one volt is therefore (1 volt) x (1.6 x 10^-19 coulombs) = 1.6 x 10^-19 joules. Thus one electron volt, one eV, is 1.6 x 10^-19 joules.

Hope this helps.

 

[rbj]

By the way your exponent is off. 6.25 x 10¹⁸ electrons make up one coulomb of charge.

Ok, this is where I am going wrong obviously. The problem is I need to be un-confused...

you're on the right track. you were asking the right question in your initial post. so now ask yourself: what is the reciprocal of 6.25 x 10¹⁸ electrons/coulomb?

 

[synoptic]

rbj wins a big fat cigar

It's nice when the obvious strikes you in the face

Cheers.

 

[bobbytkc]

I think you are confused with the extra negative power, i.e from 18 to -19.

the reason is 1 divided by 6.25 gives 0.1602, and writing that in standard form gives 1.602 x 10^-1, giving you an extra negative power, so the charge is not 1.602 x 10^-18 but 1.602 x 10. -19 .