Questions tagged [potential]
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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Empirical equivalence of shifted chemical potential $\mu_i$
It is often said that, in classical thermodynamics, entropy $S$ and energy $U$ are defined only up to an additive constant proportional to the total amount of substance $N=\sum_i N_i$ (where the sum ...
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Tensor/Vector decomposition/representation & DOF arguement [closed]
In fluid mechanics, for irrotational flow it is sometimes useful to present the velocity, $U$ in terms of a scalar potential $\Phi$ as:
$$\vec{U}=\nabla \phi$$
$\vec{U}$ has 3 dof. $\phi$ has 1.
Why ...
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The vector potential of a (rigid) electron beam
I am reading Xiujie Deng, Theoretical and Experimental Studies on Steady-state Microbunching. I am trying to figure out how Equation (4.1) regarding the electrodynamic vector potential is derived. I ...
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In the formula of capacitance of a conductor the $V$ is potential of conductor once fully charged or initial potential of conductor used to charge it
capacitance $C=q/V$
The $V$ here is the final potential of the conductor which is to be charged or the initial potential of the source conductor? We are not charging it by using a battery rather ...
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Effects on net Electric Potential with the insertion of a dielectric into a network of two capacitors in series?
Suppose you have a circuit with two capacitors of equal capacitance C, C1 and C2 that remain connected to a battery at all times. A dielectric is then fully inserted between the plates of C1. What, if ...
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Gravitational potential energy of a galaxy
How can the total gravitational potential energy of a galaxy be calculated?
Lets assume for simplicity that the entire galaxy follows an exponential mass density function for an infinitely small ...
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Finding the electric potential at the vertex of a uniformly charged conical surface... What did I do wrong? [closed]
Find the electric potential at the vertex of a uniformly charged conical surface. Let the surface charge be denoted by $\sigma$, and the radius of the base equals the height which we will denote by $...
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Some books write $V(\vec{r})$ instead of $V(r)$ as a notation for the electric potential, so which one is right? [closed]
Some books write $V(\vec{r})$ instead of $V(r)$ as a notation for the electric potential, so can the electric potential depends also on the direction?
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$U=qV$: is my understanding right?
Suppose a point charge (q) moves from point A to point B, only under the influence of an external charge configuration.
ΔU=qΔV: The change of the potential energy of the charge+external configuration ...
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Compute either only the attractive term or the repulsive term in Lennard-Jones [closed]
The Lennard-Jones potential is typically expressed mathematically as:
$$ V(r) = 4 \varepsilon \left[ \left(\frac{\sigma}{r}\right)^{12} - \left(\frac{\sigma}{r}\right)^{6} \right] $$
where:
$V(r)$ ...
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I can't use $\int \frac{kdq}{\mathcal{r}}$ to calculate the electric potential of an infinite charge distribution, can I?
Since $\int \frac{ kdq }{\mathcal{r}}$ assumes infinity is the reference i can't use it to calculate the electric potential of an infinite charge distribution, right?
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Is there an error in this Wikipedia article: "Landau quantization"?
I am trying to do a homework, so I had to consult this Wikipedia article Landau Quantization where it is mentioned that for the symmetric gauge $\vec{\textbf{A}} = \frac{1}{2}(-\textbf{B}y, \textbf{B}...
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Does electric potential give electron mass as same as higgs field?
Inside negatively charged ball there is constant electric potential. If electron will be placed inside ball with constants potential will it give mass from electric potential as same as higgs field ...
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Reference point of potential in case of a battery
When we define electric potential of a charge,we need to take a charged body as a reference and then we bring the test charge to calculate the electric potential. Now,electric potential energy is ...
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Liénard-Wiechert potentials in General Relativity
In linearized gravity, we have.
$$
\Box \bar{h}_{\mu \nu} = -\frac{16 \pi G}{c^4} T_{\mu \nu}
$$
Solving the equationg for a point mass, with a trajectory $\mathbf r_0(t')$:
$$
\rho(\mathbf r', t') = ...
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Is the strength of the charge equal on all points on an equipotential surface? [closed]
Since the equipotential is calculated by $V = q\cdot \frac{k}{r}$ I suppose that the charge is the same at any point on an equipotential surface but I'm not sure.
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Why does the Yukawa potential fail for the strong force? [duplicate]
The gluon is a massless particle, so according to the Yukawa potential the strong force should have a $r^{-1}$ potential. However, that is clearly not the case.
Is it because the gluons themselves can ...
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If a loop is not complete, and magnetic field passing through it is changing; will their be emf induced in the loop?
In a setup like the one show in the figure:
Will there be an induced EMF across the loop(given that the field is increasing)?
(my dilemma is : since the loop is not complete, we cannot define the ...
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On transition of electrons between energy levels / potentials
In an electric circuit, electron flows from the negative terminal of a voltage source to the positive terminal, which in turn, gives us the the conventional direction of electric current. So, the ...
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Question about electric potential
Suppose I take a hollow spherical conductor with inner radius $a$ and outer radius $b$. I put a charge $+q$ at the centre of the conductor (in the hollow region.) What will be the potential inside the ...
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Does Elastic Potential exist?
In gravitation, we have gravitational potential energy U and gravitational potential Φ where: $$Φ = \frac{U}{m}$$
In electrostatics, we have this instead: $$Φ = \frac{U}{q}$$
In a spring-mass system, ...
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Interpretation of gravitational waves
A wave has peaks and valleys. I can think of a sine wave as a wave with peaks and valleys.
Now, if gravity is a wave, can we say that gravity would have peaks and valleys, with the valley becoming ...
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Apparent flaw in Griffiths EM on solving Laplace's equation
I'm going through Griffiths EM and I've come across an example on how to solve Laplace's equaton through separation of variables, trying to convert a partial differential equation into an ODE, which ...
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Why do spiral arms occur at potential minima?
I've been learning about the density wave theory of spiral arms, and also how the gravitational potential of galaxies is non-axisymmetric, resulting in a sinusoidal spiral potential.
I've then learnt ...
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Electric field becomes non-conservative in electrostatic problem
This question is about what I think was a misinterpretation of the statement of an exercise. But first I have to give some context. The question is at the end.
During a class, my professor wrote the ...
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A problem of an equipotential hollow sphere
I was given the following exercise:
There are two concentric hollow spheres of radii $a$ and $b$ as shown. The inner sphere is connected to a constant potential $V_0$ while the outer sphere has ...
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Gravitational binding energy of a part of system
I want to calculate the gravitational binding energy of a small central cube (length $l$), which is part of a much larger cube (length L). I have the mass and gravitational potential distribution ...
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How to obtain the matter Lagrangian from the stress-energy-momentum tensor $T_{\mu\nu}$?
I have obtained the components of stress energy momentum tensor
\begin{align}
T_{tt}&=\frac{\Phi^2}{2\pi\mathcal{G}r^2 \left(1+2\Phi\right)^3}\\
T_{rr}&=-\frac{\Phi^2}{2\pi\mathcal{G}r^2 \...
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Fourier transform of electric quadrupole potential
I'm struggling to find the scattering amplitude by the first Born approximation (Fourier transform) given by
$$
f(\vec{k}_f,\vec{k}_i)= -\frac{1}{2\pi}\langle \vec{k}_f | {V}| \vec{k}_i\rangle = -\...
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Does KVL don't hold in pn junction reverse bias?
Does KVL hold in pn junction reverse bias because any reference about semiconductor physics provide that figure
if we apply KVL around the loop won't be zero it will be equal to $V_{bi}$
then how KVL ...
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Why Does equipotential surfaces gets father apart in the regions of weak electric field?
If we consider a charge in space then we can draw infinite number of spheres (taking the distance between the spheres equal) around the charge and these spheres act as equipotential surfaces. Now, As ...
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Does the built-in potential inside a diode change by making bias?
under thermal equilibrium the pn junction have a built-in field let say it's $E_{1}$ , if we make a reverse bias the external battery provide a permanent field $E_{2}$ , so the total field inside the ...
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Violation of energy conservation due to Lorentz Force?
We know that work done by Lorentz Force $q(\vec{v}\times\vec{B})$ is $0$ on moving charge in magnetic field as velocity is always perpendicular to the force. This means that kinetic energy remains ...
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Does negative charge move from lower potential to higher potential?
This image implies that charge flows from a higher potential to lower potential….but if we attack a battery to a circuit then the current will flow from lower potential (positive terminal) to higher ...
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Difference between local and non-local optical model potential?
As far as I understand, local OMP (optical model potential) depends only on the relative position, and non-local OMP depends on relative position and momentum.
I am searching for more information so ...
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Relation between ground state energy and the potential
I am given the following Hamiltonian:
$$H = \frac{p^2}{2m} + \lambda|x|^3$$
where $\lambda$ is a positive constant.
Is there a relation between the ground state energy of $H$ and $\lambda$ i.e. is ...
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EMF Generated according to Faraday's Law
According to Faraday's Law, due to a relative movement between the current carrying loop and the magnetic field, an EMF is induced in the loop causing a current flow. However, according to Maxwell-...
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Potential Difference and Electrical Potential [duplicate]
What is the difference between Electrical Potential and Potential Difference?
Please try to explain in layman language
Any response would be apriciated
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Is the magnetic vector potential "real" in classical electromagnetism?
From how I've learned it in school the magnetic vector potential is used as a mathematical tool to simplify problems with current-carrying wires in classical electromagnetism, but is never treated as ...
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Trouble understanding the electrostatic field's curl [duplicate]
I'm going over Griffiths Electromagnetism, and I've encountered a sort of proof about why we can state an electrostatic field is conservative, using Stokes' theorem. Of course, I do understand if you ...
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Potential inside a Charged Conductor near another Charge
Let's say that we have a solid conducting sphere with radius r and this conductor is given a positive charge of q1. We know that the charge will get distributed on the surface to reduce field inside ...
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Electric potential of uniformly charged wire with Green function
I want to calculate the electric potential of a uniformly charged wire with infinite length $\rho(\vec{r}') = \lambda \delta(x') \delta(y')$ with Green function $G(\vec{r}, \vec{r}') = \frac{1}{4\pi \...
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Average electric potential over a spherical volume [closed]
I know the average potential over a spherical surface equals the potential at the center of sphere.
But is it also true for average over spherical volume ?
In both cases the sphere is empty of charge.
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Potential of a Polarized Object in Griffiths
I have some slight confusion regarding how Griffiths (4th ed) gives the potential of a polarized object in chapter 4. He asserts that the potential of a point dipole is:
$$V(\boldsymbol{r})=\frac{1}{4\...
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How and why does an electrometer measure the potential differences?
It was written in my school physics book that because any conductor surface is equipotential, if we have the two plates of a conductor and if we connect them to an electroscope then the change of ...
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Voltage between two points in a circuit without any resistance [duplicate]
Consider two points A and B in a circuit which have no resistance between them. If we assume current flows through the part AB from A to B, then that means there must be a nonzero potential difference ...
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How current can pass through a part of circuit if potential difference between two points is zero? [duplicate]
Since the wire has no resistance there how can current flow in the circuit between points A and B? If current doesn't pass through them then the circuit doesn't have current
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What's the meaning of a lack in $V$ if the resistance is zero? [closed]
We know that $V=RI$. If $R=0$ then $V=0$ regardless of the amount of $I$. There is the conduct, because we have displacement of $q$ in the formula $q=It$. But what's the meaning of a lack of $V$?
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What exactly does it mean that a charged body has potential $V$?
Does it mean it takes $V$ joules of energy to move a unit positive charge from infinity to that body?
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If a force equal and opposite to the electrostatic force is applied on a charge, how can the charge move in the electric field? [closed]
For measuring the electric potential difference between two oppositely charged plates A and B, a test charge q is moved from plate A to plate B.
My textbook says that the charge is kept in ...
