7
votes
Accepted
3 Aspects of Voltage that contradict each other
Basically the problem here is using the same words for similar and related concepts that are nonetheless not identical. The fundamental concept that is behind "voltage" is the concept of ...
- 2,367
7
votes
Accepted
Double and single delta-function potential well energy similarity
As the two delta peaks are pulled apart, they influence each other less and less. In the limit $a \to \infty$, the bound state energies are completely determined by the bound state energies of a ...
- 6,990
5
votes
3 Aspects of Voltage that contradict each other
1- Voltage is Potential Difference: Voltage is the difference between
the energy levels.
The potential difference between two points is the work required per unit charge to move the charge between ...
- 75.7k
4
votes
Why many times $E= -{\rm grad} V$ does not give correct direction of the $E$?
This is my answer to your original question.
I'm afraid that you go wrong very near the beginning of your question. In your first paragraph you ask us to "consider two points, one on positive 𝑧 ...
- 36.2k
3
votes
Why is charge on a conductor stable?
Yes that's right, for a charged conductor the electric field outside the surface is directed such as to pull charge off the surface. The reason the charge doesn't leave the surface is to do with what ...
- 60.1k
2
votes
Accepted
Electric Potential simple questions
How can a P charge can move even though it has zero potential?
Because the force is not determined by the value of the potential. The force is determined by the slope of the potential.
Because a ...
- 22.4k
2
votes
Vector Potential and Electric Field
Yu uses cgs units. In cgs units, the electric field is
$$\vec{E} = -\frac{1}{c}\frac{\partial \vec{A}}{\partial t}\ , $$ (see eqn. 6.24 in Yu)
and $c =\omega/q$.
If $E = E_0 \sin(\vec{q}\cdot \vec{r} -...
- 135k
1
vote
Electric Potential simple questions
You're right; the potential at point $P,$ due to one positive charge and one negative charge, does sum to zero. But the positive charge $q_P$ at $P$ still feels a force, despite the potential at the ...
- 412
1
vote
Accepted
Vector Potential and Electric Field
In page 260 the conjugate term is explained: it's used so that $A$ is a real function. Remember that $e^{ix}+e^{-ix}=2\cos x$. As for the constant terms that appear in the equation for $A$, I think it ...
- 2,367
1
vote
3 Aspects of Voltage that contradict each other
Perhaps the best mental picture for voltage is elevation. Taking Gravitational Potential Energy $E_g= mgh$ divided by the mass, gives us Gravitational Potential:
$$V_g= \frac {E_g}{m} = gh$$
And since ...
- 10.1k
1
vote
Representing gravity as spherical harmonic expansion causes divergence at poles
I didn't check your math, but I don't think there is a divergence.
It seems implied in the question that you are talking about the gravity of a spherical planet, maybe rotating--possibly Earth.
This ...
- 36.7k
1
vote
Relation of field of force to potential energy
According to the multivariable chain rule the total differential of a multivariate function, for example $f(x,y)$, is:
$$\mathrm df = \frac{\partial f}{\partial x}\mathrm dx + \frac{\partial f}{\...
- 1,351
Only top scored, non community-wiki answers of a minimum length are eligible