Confused on the Electrical Energy Formula?

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
1 reply · 2K views
012anonymousx
Messages
46
Reaction score
0
This is probably a silly question.

The Electrical energy formula is this:
Ee = k(q1)(q2)/r

So let's say a positive and negative charge are directly next to each other.
Conceptually, there should be no potential energy there.
But the formula (r=0.00001m) suggests that it is huge.

On the other end, if two positive charges are far away from each other (r=1000), energy should be huge, but the formula suggests it gets smaller.

I appreciate all the help!
 
Physics news on Phys.org


012anonymousx said:
But the formula (r=0.00001m) suggests that it is huge.

Actually, it says it should be hugely negative, as q1q2 is negative. Bringing them apart (increasing r) should increase the potential energy, which makes sense, as it takes energy to move them apart. (Note that the concept of negative energy might seem counterintuitive at first, but, by gauge symmetry, the only thing we care about is the difference between two energies in a potential field.)

On the other end, if two positive charges are far away from each other (r=1000), energy should be huge, but the formula suggests it gets smaller.

On the contrary, the energy should be tiny, as you have to pour in some energy to overcome the force repelling the charges.