The potential tag has no wiki summary.
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Potential of a Body
I have a doubt about the electric potential of a body. Well, I know that given a continuous distribution of charge we can find the potential at a point $a$ using the following relation:
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1answer
801 views
How to solve Schrodinger Equation - Tunnelling
I have to solve analitically the Schrodinger equation in one-dimension with a barrier of potential (tunnel effect):
$$ih \frac{d}{dt} U(x,t) = \left[ \left(-h^2 \frac{d^2}{dx^2} \right) + q V(x) ...
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1answer
36 views
The potentiality of the electric field
Could you, please, explain me using just words why electric the field is potentially? I know the proof using integral: $A = \int_{12}q\overrightarrow{E}\overrightarrow{dr} = ...
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1answer
26 views
Potential of a conductor depends on the size and shape of the conductor. How?
1) When a charge 'q' is given to an isolated conductor, its potential will change.
2) The change in potential depends on the size and shape of the conductor.
I could understand the point no. 1. ...
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2answers
51 views
Electron in an infinite potential well
Does this problem have any sense?
Suppose an electron in an infinite well of length $0.5nm$. The state of the system is the superposition of the ground state and the first excited state. Find the ...
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2answers
51 views
Convolution kernel of poisson equation by FFT
I'm trying to solve poisson equation using FFT. In genral it is a convolution of the charge density with potential well of point charge ( Green's function of laplace equation ) which is $1/r$
I'm ...
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0answers
35 views
tricky electric potential [closed]
I have this question: $q_1$ is a Uniformly Charged long Wire(inf in z axis) with $\lambda$ (charge per unit length).
In (0,0,0) I have A very long conducting cylinder of radius a (also inf in z axis). ...
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1answer
262 views
( Legendre Generating Function) Off axis Electric Potential from an insulated disk
An insulated disk, uniform surface charge density $\sigma$, of radius $R$ is laid on the $x,y$ plane. Deduce the electric potential $V(z)$ along the z-axis. Next consider an off axis point $p'$, ...
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6answers
329 views
Electrostatic Potential Energy Derivation
How is the boxed step , physically as well as mathematically justified and correct ?
Source:Wiki http://en.wikipedia.org/wiki/Electric_potential_energy
As work done = $- \Delta U $. for Conservative ...
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1answer
103 views
Spring Constant
Is it possible to determine the spring constant of a spring in a situation in which it is being compressed when such certain length of compression is not known? If so, how can such calculation be ...
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1answer
219 views
In the Lennard-Jones potential, why does the attractive part (dispersion) have an $r^{-6}$ dependence?
The Lennard-Jones potential has the form:
$$U(r) = 4\epsilon\left[ \left(\frac{\sigma}{r}\right)^{12} - \left(\frac{\sigma}{r}\right)^{6} \right]$$
The (attractive) $r^{-6}$ term describes the ...
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1answer
152 views
Electric field of a flat metal plate and a point particle
I'm currently studying electric potential, and I'm having trouble with one of the problems on my homework:
A) A point particle with charge $+q$ is on the x-axis at a distance $d$ from the origin, ...
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4answers
952 views
Electric potential vs potential difference
What is the difference between electric potential and potential difference? In our course book, they are given as separate topics but their definition is given the same.
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2answers
116 views
Lorenz gauge fixing
Is it always possible to define function $\psi$ satisfying the Lorenz gauge equation
$$
\partial_{\mu}\partial^{\mu} \psi + \partial_{\mu}A^{\mu} = 0?
$$
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2answers
51 views
Electrostatic Potential Definition
In the book, Introduction to electrodynamics by David J. Griffiths, he introduces potential separately as a function and potential energy through that function.
How can potential be defined before ...
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1answer
341 views
Bound states for sech-squared potential
I'm working on an introductory qm project, hope somebody has the time to help me (despite the length of this post), it will be highly appreciated.
My goal is to determine the bound states and their ...
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0answers
45 views
Electric Potential and Electric field intensity [closed]
A hollow charged metal sphere has a radius r . If the potential difference between it's surface and a point at a distance 3r from the center is V, then the electric field intensity at a distance 3r ...
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1answer
45 views
How to find Electrostatic Potential Difference?
I have a really simple doubt about finding the potential difference in electrostatics. Well, first of all, the definition of potential difference is very clear to me: we take a path between the points ...
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5answers
106 views
Workdone in an equipotential surface is zero?
An equipotential surface is one in which all the points are at the same electric potential. If a charge is to be moved between any two points (say from point A to point B) on an equipotential surface, ...
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4answers
756 views
In quantum mechanics, given certain energy spectrum can one generate the corresponding potential?
A typical problem in quantum mechanics is to calculate the spectrum that corresponds to a given potential.
Is there a one to one correspondence between the potential and its spectrum?
If the ...
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1answer
103 views
Potential in Relativistic Scalar Field Theory
My intention is to establish a Soliton equation. I have cropped a page from Mark Srednicki page no 576.
I have understand the equation (92.1) but don't understand that how they guessed the ...
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1answer
50 views
Electric field and potential [closed]
An oil drop of radius 0.70mm containing a charge of -4.8 x 10-19 C is placed in an electric field if the drop remain stationary at the point find the magnitude and direction of electric field ...
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1answer
61 views
How to superimpose Wood-Saxon and Coulomb potential?
I have just written a simple simulation that models the tunnel-effect of alpha-particles for $^{212}$Po and $^{238}$Ur. In this simulation, I approximate the potential of the nucleus by a simple ...
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2answers
134 views
Why does a capacitor discharge?
Suppose a charged capacitor (parallel plates), the negative and positive charges on two plates attract each other. Which force cause the negative charge carriers (electrons) move through the circuit ...
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1answer
140 views
Finite, square, potential well
Lets say we have a finite square well symetric around $y$ axis (picture below).
I know how and why general solutions to the second order ODE (stationary Schrödinger equation) are as follows for ...
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1answer
105 views
Finite potential well - transcendent equation for even solutions
I have a finite square well like the one on the picture below:
I have done some calculations on it and got a transcendental equation for even solutions which is like this:
$$
...
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1answer
92 views
Energies and numbers of bound states in finite potential well
Hello I understand how to approach finite potential well (I learned a lot in my other topic here). However i am disturbed by equation which describes number of states $N$ for a finite potential well (
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2answers
277 views
Plotting $\psi$ for finite square well potential
Lets say we have a finite square potential well like below:
This well has a $\psi$ which we can combine with $\psi_I$, $\psi_{II}$ and $\psi_{III}$. I have been playing around and got expressions ...
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0answers
40 views
Wave equations for two intervals at Potential step
Lets say we have a potential step as in the picture:
In the region I there is a free particle with a wavefunction $\psi_I$ while in the region II the wave function will be $\psi_{II}$.
Let me ...
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0answers
33 views
Is it easier to determine the number of states with raising/lowering operators or using scattering?
A particle is bound by
$$V(x) = \begin{cases}\infty,& x <0 \\ \frac{-32\hbar^2}{ma}, & x\le a \\ 0, & x \le a\end{cases}$$
a) how many states are there?
i'm attempting ...
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1answer
220 views
Non conducting charged planes
I have two parallel non conducting charged planes with opposite charges $6\mu C/m^2$, area $A = 3m^2$ and distance between the planes $d = 0.004 m$. I know the potential between these two planes is ...
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1answer
88 views
Is it possible to charge a capacitor to any potential? Does it depend on the dielectric placed between them?
Is it possible to charge a capacitor to any potential? Does it depend on the dielectric placed between them? Or, are there other factors affecting it?
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2answers
451 views
Particle in infinite potential well which is doubled in size at $t_0$
I am currently studying for an exam in Quantum Mechanics and came across a solution to a problem I have trouble with understanding.
The Problem:
A Particle sits in an infinite potential well ...
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1answer
63 views
Electric charge and the distance
The strength of an electric field is: $E = 200\ \mathrm{N/C}$
The potential (of the test charge) is: $V = 600\ \mathrm{V}$
$\epsilon_r=1$
I need to calculate the distance between this point and the ...
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1answer
135 views
Electron volt and Voltage
Voltage is the work done per unit charge. Given by:
V = W/q
Electron volt is the maximum kinetic energy gained by the electron in falling through a potential difference of 1 volt. Given by:
K.E ...
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1answer
46 views
how quantum-mechanical particles react in the potential?
I am reading some materials on quantum mechanics. I am a bit confusing in the chapter on wave-particle duality and following questions arise
In classical mechanics, the force a particle experience is ...
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1answer
455 views
Gradient of the electric potential
I was wondering if for a point-like charged object, does the gradient of the electric potential point in the direction of maximum increase or maximum decrease of the function $V$?
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2answers
59 views
Wavefunction restrictions of odd potentials
So I was just reading back through Griffiths' "Introduction to Quantum Mechanics" and solving some of the problems for practice. There is a nice one (problem 2.1c for those playing at home) where you ...
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6answers
302 views
Is voltage electric potential or electric potential difference?
On Wikipedia, voltage is defined to be the electric potential difference. However, I am still not certain as to whether voltage is the electric potential ($PE/q$) or electric potential change ...
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1answer
62 views
Locally every force admits a potential?
I have a little doubt about a force being or not conservative. Well, as I understood, some forces cannot be expressed as exterior derivative of some scalar potential because the work done by the force ...
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2answers
218 views
Why is electric potential scalar?
I can't conceptually visualize why it would be so. Say you have two point charges of equal charge and a point right in the middle of them. The potential of that charge, mathematically, is proportional ...
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2answers
270 views
Higher To Lower Electric Potential
The question I am working on is:
"An electron moving parallel to the x axis has an initial speed of $4.65 \cdot 10^6~m/s$ at the origin. Its speed is reduced to $1.27 \cdot 10^5 ~m/s$ at the point ...
4
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1answer
121 views
Kaluza-Klein Christoffel Symbols
I have a question regarding the connection coefficients as they pertain to the following paper: http://www.weylmann.com/kaluza.pdf . When I try to calculate the 4D Christoffel symbols from the 4D part ...
4
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1answer
268 views
How to interpret the magnetic vector potential?
In electromagnetism, we can re-write the electric field in terms of the electric scalar potential, and the magnetic vector potential. That is:
$E = -\nabla\phi - \frac{\partial A}{\partial t}$, ...
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2answers
86 views
How can one determine at which distance the Lennard-Jones potential reaches a given value?
My question is fairly simple, but I do need clarification on how to get the inverse of the Lennard-Jones potential V(x).
I am working with the following expression:
$$
V(x) = e\times[(R/x)^{12} ...
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2answers
248 views
Vector Potential and Gauge Invariance in Quantum Mechanics
In classical electromagnetism, we are allowed to use gauge invariance through the argument that the only physical observable fields are the $E$-field and the $B$-field. So in that sense the scalar ...
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2answers
246 views
How can you have a negative voltage?
How can you have a negative voltage? I don't really understand the concept of negative voltage, how can it exist?
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1answer
376 views
Maxwell's Correction to Ampere's Law
I have not yet officially studied Electromagnetism but am trying to teach myself at the moment. I understand Maxwell's equations in the context of Magneto- and Electrostatics: they are equivalent, ...
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1answer
107 views
Linear dependence of magnetic potential on current density
I'm a mathematician learning physics to provide some background for my mathematical work (especially pde's!). I have been reading through Jackson's Classical Electrodynamics (3rd edition), and I was ...
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2answers
104 views
Elastic potential
I have a doubt:
elastic potential energy is given by: $U=\frac{k}{2}x^2+K$
but does elastic potential exist? (for example: potential gravitational energy is given by $U=mgz+K$ and gravitational ...
