Easy Electric Potentional Problem

[exitwound]

Homework Statement

The electric potential difference between the ground and a cloud in a particular thunderstorm is 1.5E9 V. What is the magnitude of the change in the electric potential energy of an electron that moves between the ground and the cloud?

_____ GeV

Homework Equations

U\q=V

The Attempt at a Solution

This should be simple.

U=qV
U=(1.6e-19)(1.5 GV)
U=2.4e-19 GeV

Why is this not right?

 

[exitwound]

Anyone? Still can't figure it out.

 

[exitwound]

NO one at all?

 

[Redbelly98]

The Attempt at a Solution

This should be simple.

U=qV
U=(1.6e-19)(1.5 GV)
U=2.4e-19 GeV

Why is this not right?

What are the units on the 1.6e-19? Include the units in the calculation.

 

[exitwound]

Coulombs. I'm not following.

 

[Redbelly98]

Correct.

That would make the units in your answer Coulombs*V, and not eV. You'll have to convert to eV (or GeV).

 

[exitwound]

So, ... what, I divide by 1.6x10^-19?

U=2.4e-19 / 1.6e-19 = 1.5 GeV

There are too many stupid units in electromagnetism! This is driving me crazy.

 

[Redbelly98]

So, ... what, I divide by 1.6x10^-19?

Yes. (Or don't multiply by 1.6x10^-19 in the first place.)

U=2.4e-19 / 1.6e-19 = 1.5 GeV

Yes, you got it.

There are too many stupid units in electromagnetism! This is driving me crazy.

You get used to it after awhile.

By the way, if you use elementary charge units instead of Coulombs here, it's simpler:

An electron has -1.00 elementary charges or -1.00 e of charge, so

U = q V
= (1.00 e) (1.5e9 V)
= ___ eV
= ___ GeV​