We’re rewarding the question askers & reputations are being recalculated! Read more.

# 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.

1,705 questions
Filter by
Sorted by
Tagged with
13 views

### Sources of Electromagnetic Potentials

I have a question regarding sources of electromagnetic potentials: As far as I know, wave equations for the scalar and magnetic vector potentials can be derived from Maxwell equations employing the ...
21 views

### Working of potentiometer to measure unknown emf

How at balancing point in a potentiometer does the galvanometer record zero deflection? Why is no current flowing at this point of time in the secondary circuit? Can someone explain what is going on ...
70 views

### What is the use of resistors connected in series?

If the current in a series circuit remains the same, then what is the use of a resistor? I read somewhere that as electrons flow through a circuit, they are accelerated towards the positive terminal, ...
57 views

### Derivation of Lagrangian of electromagnetic field from Lorentz force

I was trying to derive Lagrangian for electromagnetic field from the Lorentz's force formula $$F= q(E + v✕B)$$ I have to find the potential by using line integral of the force. I have wrote the above ...
42 views

### Explicit form of S-matrix on the line

Consider the Hamiltonian $H$ on functions on the line with \begin{eqnarray} H=H_0+V,\\ H_0=-\frac{1}{2m}\frac{d^2}{dx^2} \end{eqnarray} where $V$ is a potential vanishing outside of a bounded interval....
104 views

### Why do we pick trigonometric solutions, instead of complex exponentials, when solving the Schrödinger equation for a square well?

I was thinking about something that I never understood when I took my QM course. If I have an infinite square well, say $V=0$ for $-a<x<a$ and $V= \infty$ otherwise. In the region of interest, ...
65 views

### Electron volt $eV$?

$1 eV$ is defined as the energy gained by an electron when accelerated through a potential difference of $1V$. But, I think when the electron is accelerated, it gets closer and closer to the source of ...
26 views

### Local density approximation: How do I get an expression for exchange and correlation for an atom?

I want to make a DFT program for an atom in the local density approximation. The user specifies the proton number and electron quantum numbers $n,l$, and the program returns the ground state energy by ...
50 views

### What determines whether we use a vector or scalar potential?

I understand that electrostatic potential is scalar because the curl of the field is zero, and this implies the electrostatic field is the gradient of the scalar potential to satisfy this. Similarly ...
32 views

### Potential Drop across a Capacitor

Let us consider an ideal parallel plate capacitor in a circuit. The capacitor is connected to a battery which generates a potential difference of V across the terminals. QUESTIONS: 1) The work ...
22 views

### Equipotential Lines

In 2D why exactly do lines of equal potential exist on a point charge at rest? This doesn't make sense to me if the point charge is hypothetically a lone charge undisturbed by other charges.
52 views

### Density functional theory: How do I derive potentials $V[n]$ from expressions for the energy $E[n]$?

In the following, suppose $n$ is the electron density and $n^\uparrow$ and $n^\downarrow$ denote the density of spin up and spin down electrons respectively. Therefore $n = n^\uparrow + n^\downarrow$. ...
82 views

### Are those two capacitors in parallel?

I'm trying to analyze the following situation: we have a parallel plate capacitor where the plates are both squares with side length $l$ and on the positively charged plate we have a charge $Q$, ...
24 views

### Electric Potential of Two Oppositely Charged Adjacent Spheres [closed]

I am confused about part d to the following question (defining the reference point $\displaystyle\lim_{x\to\infty}\phi(x)=0$). My instructor has told me that $\displaystyle\lim_{x\to-\infty}\phi(x)=0$...
22 views

### A vector potential of a magnetic field and the gauge freedom of the Lagrangian

I'm currently studying a course of mechanical analytics. we used some terms that I just can't wrap my head around. I was wandering if anyone could explain\refer me to a good place to read about it: ...
95 views

### Calculating the point charge potential via Gauss's law

I want to calculate the potential of a point charge via Gauss's law $$\vec{\nabla}\cdot\vec{E}=4\pi\rho(\vec{r})$$ My Idea: we can find an expression for $4\pi$ that has the form of an integral, by ...
20 views

### Multipole expansion

consider a charge distribution say q, 2q, 3q, kept on the vertices of an equilateral triangle. There exist monopole, dipole ,qudrupole etc terms in the potential expression. these 3 charges are ...
21 views

### Quantum scattering from delta potential Barrier and well

Scattering from delta potential potential at $x=0$ it is observed that for $E>0$ both for potential well and barrier the reflection and transmission coefficient becomes same.As, in both the context ...
27 views

### Is electric potential of the grounded conductor of a capacitor always zero?

In a spherical capacitor, the net electric potential on the outer grounded conductor due to the positive charge on the inner conductor and the negative charge on the outer conductor is always zero. Is ...
11 views

### Spectrum of an operator with a center of attraction [duplicate]

What can we qualitatively say about the spectrum of a Hamiltonian operator if the spectrum is not bounded from below but bounded from above? e.g. $$\mathcal{H}=-\frac{d}{dx^2}-\frac{\lambda}{x^2}$$ ...