# Tagged Questions

Scalar and vector potentials in electromagnetism. The scalar potential is potential energy per unit charge. For potential energy, use the potential-energy tag.

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### Potential Difference of a wire?

Imagine a circuit with only a 12 Volts battery and a wire connecting the ends of the battery. Point A and point B lies on the wire. What is then the potential difference between point A and B if the ...
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### Bohr-Sommerfeld quantization for different potentials

Let's have Bohr-Sommerfeld quantization for one-dimensional case: $$\int \limits_{a}^{b} p(x)dx ~=~ \pi \hbar (n + \nu ).$$ Here $p(x) = \sqrt{2m(E - U)}$, $a, b$ are turning points, and the area ...
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### Bound states in 1D & 2D [duplicate]

Why does Mother Nature allow bound states in arbitrarily weak attractive potential in 2D but not in 3D? See, for example, this article, arXiv:math-ph/0208011.
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### What does raising voltage do?

If I raise the voltage of a wire from 0V to 1000V and then to 5000V, am I merely packing it with more and more electrons (with those electrons being trapped there until they find a path off the wire)? ...
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### Potential difference between point on surface and point on axis of uniformly charged cylinder

Question: Charge is uniformly distributed with charge density $ρ$ inside a very long cylinder of radius $R$. Find the potential difference between the surface and the axis of the cylinder. Express ...
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### Nonlocal interaction effects on bose-einstein condensates

I'm studying an interacting bose-einstein condensate using the energy functional proposed in this paper K. Huang, C.N. Yang, Phys. Rev. 105  E\left[\phi\right] = \int d^3\vec{r} ...
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### The Effect of Tortoise Coordinates

Referring particularly to http://arxiv.org/abs/hep-th/9909056 in regard to the wave equation for Schwarzschild-AdS black holes (p.4), I'm trying to understand tortoise coordinates. So starting ...
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### Special case of work done by two opposing forces of equal magnitude on a body possesing inertial motion

Consider an elevator moving upward with constant velocity. The constant velocity is maintained by an upward tensional force equal to weight. If we add the total work done on the elevator it will be ...
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### Why is electric potential positive?

If there is a positive charge $q$ at the origin of a coordinate system, the electric potential $\phi$ at a distance $r$ from $q$ is (by definition, if we take the point of zero potential at infinity): ...
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### Name of battery voltage when load connected/disconnected

If I had a 3V battery, and when no load connected it reads 3.2V, and with a load 2.8V (just a hypothetical example), what is the name for these two terms, with a load or no load? I know the voltage ...
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### Potential energy of a dipole in a uniform electric field convention?

When finding the potential energy of a dipole in a uniform electric field, I was told by my lecturer that the convention is that the potential energy is 0 when the dipole moment and electric field ...
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### Modeling a potential well

I attempted to simulate the interaction of a moving particle and a potential well in Mathematica. The particle should experience a force of -$1/r^2$, if the equation for the potential well is -$1/r$. ...
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### Is the “Force” of Gravity Simply Hamilton's Principle on a Curved Spacetime?

It's my understanding that General Relativity abstracts away the concept of gravity as a force, and instead describes it as a feature of spacetime by which massive objects cause curvature. Then it ...
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### What is physical meaning of $|\phi|^2$ in quantum field theory and pedagogical spontaneous symmetry breaking?

If wavefunction is $\phi$, we know that $|\phi (x)|^2$ represents probability of finding a particle at $x$. Now let us talk about some pedagogical example in spontaneous symmetry breaking in QFT, ...
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### When to use method of images in Electrostatics?

I am a bit confused about when to use the method of images in E&M? For example, in Griffith's Electrodynamics Example 3.2, the problem reads: A point charge $q$ is situated a distance $a$ from ...