# 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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84 views

### Ambiguity between electric potential and voltage?

I understand that electric potential is a location based measure of electric potential energy per unit charge in an electric field, and that voltage is then the difference between two electric ...
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### Charged conductor in an external electric field

If we put a conductor in a place where there is a uniform electric field, then the field will change. Take for example the case of a conducting cylinder, then the field lines would curve to return ...
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### What is the quantum mechanical turning point of the $n^{th}$ energy eigenstate of an oscillator? [closed]

I am looking for an analytical expression for the most likely position for a quantum harmonic oscillator (which I refer to as the quantum mechanical "turning points"), in terms of $n$. For the quantum ...
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### On proving that charge is linearly proportional to potential for a conductor

In Mr. Purcell's Electricity and Magnetism, page 103, it is stated, An isolated conductor carrying a charge $Q$ has a certain potential $\phi _{0}$, with zero potential at infinity. $Q$ is ...
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### One-dimensional Schrödinger equation: reproducing a given set of energy values [duplicate]

Given a set of $N$ increasing real numbers $\{E_1, E_n, \cdots, E_N \}$, is it always possible to find a potential $V(x)$ such that the set of $\{E_j\}$ are the lowest eigenvalues of the corresponding ...
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### Is the $E$-field near and on the outer surface of a conductor null?

Let us say we have a conductor the outermost surface $S$ of which is given by $$S: \big(\,x(u,v),\, y(u,v),\, z(u,v)\,\big )$$ where $u$ and $v$ are parameters. Since it is a conductor, the ...
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### Summation of piezoelectric potentials

I am looking at surface acoustic wave devices, these are piezoelectric circuit components. They use an electrode pattern, called an inter-digital transducer (IDT) to produced and receive Rayleigh (or ...
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### Gravitational Potential Derivation

The definition of Gravitational Potential at a point is the work done per unit mass in moving it from infinity to that point. However the work is positive and if you perform the integral you get a ...
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### What's the intuition for the reflection of a quantum particle at a potential step equal to the particle's energy?

While doing the problem of potential step, I saw that if the energy of the particle is equal to the potential energy of the step, then the wave function is a constant, or to say the probability ...
48 views

### Odd potentials in TISE

When we have an even potential we say that it has an even and odd parity wavefunctions, cf. e.g. this & this Phys.SE posts. What about an odd potential? For example, two delta functions centered ...
161 views

### From Poisson's equation to Laplace's equation [closed]

I want to understand how exactly $$\nabla^2 V = - \frac{\rho}{\epsilon_0}$$ turns into $$\nabla^2 V = 0.$$ Of course it is by setting $\rho$ equal to $0$ but what does setting $\rho$ equal to $0$ ...
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### Why are so many (all?) Key concepts in thermodynamics derived from a legendre transformation? [duplicate]

Given a function $f(x,y)$, a legendre transform w.r.t. $x$ is $f^*(p,y)=p x - f(x,y) |_{p=\frac {\partial f(x,y)}{\partial x}}$. E.g. , the various free energies, enthalpy, etc are all legendre ...
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### On setting the potential of this conducting sphere to zero

Let us say we have the following setting: Two conductors with potentials $\phi _{1}$ and $\phi_{2}$ (with the zero set to infinity) enclosed within a hollow conducting shell having zero charge. How ...
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### What is the work done in bringing a charge from infinity to the location of another point charge?

Consider a positive charge $Q$ at the origin.What is the work done in bringing a unit positive charge from infinity to zero. We know that the work done in bringing the charge from infinity to $r$ is ...
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### How do you calculate a half cell potential Copper(II) and Copper Sulfate?

I have to complete an experiment for school where I have copper and zinc electrodes placed into an electrolyte of copper sulfate and I have measured the potential across it at varying temperatures. ...
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### Can electric fields pass through grounded surfaces?

Let's assume there is a grounded surface with which is infinite in length and width. If my understanding is correct, the grounded surface should have zero electric potential. So, if we assume an ...
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### Metal sphere in uniform Electric Field—doesn’t behave like dipole at large r?

I’m going over Griffiths EM example 3.9 (different question on this example is here Metal Sphere in a Uniform Electric field). I’m wondering where the logic for V\rightarrow -E_0z= -E_0r\cos(\theta)...
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### Do potentials make sense in relativistic quantum theory?

In Peskin & Schröder QFT, just before equation 7.93, he writes in passing, Next let us examine how $\Pi _2 (q^2)$ modifies the electromagnetic interaction, as determined by Eq. (7.77). In the ...
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### Electric potential difference between coaxial cables clarification

https://www.youtube.com/watch?v=hJPWs0Gf2SU In this video, he derives an expression for the potential difference between the two radii R2 and R1 where R2>R1 He arrives at the derivation by ...
68 views