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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Sturm Liouville potential

How to determine the potential function of a Hamiltonian, given by a general second order differential equation using the Sturm-Liouville theory? Of course, any other approach is also appreciated. ...
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Transformer primary and secondary coil current problem

A step up transformer has 300 turns on its primary coil and 90,000 turns on its secondary coil. The potential difference of the generator to which the primary circuit is attached if 60 V. The ...
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Do wires have a potential difference? Why? [on hold]

I just want to know: do all conductors have potential difference? What about wires or bulbs specifically? Where does this difference lie?
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Do energy levels such as $E_c$, $E_v$ have negative values in semiconductors?

In energy band diagram of a semiconductor, do energy levels such as $E_c$, $E_v$ have negative values? Also, why electrons in semiconductor have energy? What is the formula for energy of an ...
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Why does a electric Potential have to be real, but not a Potential in quantum mechanics?

So I had this Problem when I had to learn about classical electromagnetism: Why is it, that we use complex numbers when calculating stuff, but in the end only the real part is important (for example ...
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Solution for Schrödinger equation for constant box potential?

It is known that in a box potential, when we set $V = 0$ inside and $V = \infty$ on the boundaries, the solution to the equation $$ - \frac{\hbar}{2m} \bigg( \frac{\partial^2}{\partial x^2} + \frac{ \...
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Electrical gradient

I'm a zoology minor and I'm trying to understand electrical gradient. I found this explanation in an authentic website but cannot undertand it fully. An unequal distribution of charges across the ...
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Potential difference between two assymetrically charged plates

What is the potential diff between two plates of charges $q_1$ and $q_2$ ($q_1$ $>$ $q_2$)? I know the equation is $V = \frac{q_1-q_2}{2C}$ where $C$ is the capacitance of the system but how has ...
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Lagrangian in a system with a specific velocity dependent potential

I have a system of a particle moving under the generalized central potential $$ V= \frac{1}{r}(1+\dot{r}^2) \tag{1} $$ The general Euler-Lagrange equations for such type of potentials are: $$ \frac{...
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Does the mass of a brick increase when you lift it? [duplicate]

If a person takes a brick, and lifts it to a height of 1 m, will the mass of the brick increase?
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How does voltage produce current?

I am studying electric current and i dont understand how does voltage(potential difference )produce current? PS : I am a 10th grade student so please avoid complicated terminologies.
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Why does there have to be an electric field if there is potential difference?

I read in a few books that there is always an electric field if there is an electric potential. I went through this but the question on this page only states that there is an electric field and it is ...
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Wavefunction of electron in 3D infinite well with non-zero potential

Consider an electron moving in a potential $V$ defined by $$V(x,y,z) = \left \{ \begin{array}{ll} \alpha(x^2 + y^2) & 0 \leq z \leq a \\ \infty & \text{otherwise} \end{array} \right. $$ ...
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How to find electric potential from electric field? [closed]

How to find potential difference when electric field is given ?
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why potential becomes equal when capacitor are connected

If we have a circuit as shown in which two capacitor are connected of unequal potential. Now if we close the switch the charge will flow till potential becomes equal. But as we know $Q=CV$, $V=Ed$...
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Final potential difference between plates of capacitor [closed]

If the plates of a parallel plate capacitor are given charges 4Q and -2Q . The capacitor is then connected across an uncharged capacitor of the same capacitance as first one (=C) . Now we have to find ...
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As distance increase why no change in electric field in parallel plate condenser [duplicate]

If the distance between the plates of a parallel condensor is 4mm and the potential difference is 60 volts. Now if we increase the distance between the plates to 12mm, then: Why the electric field ...
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Can someone explain me magnetic potential? [duplicate]

I don't understand why we can write the magnetic field as a potential vector A, and what exactly this potential is. Is it just a mathematical thing? And how can it help me calculate the magnetic ...
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How to Explain the the following situation?

I have thought a simple thing: consider a system of a planet and its natural satellite revolving around it in a perfectly circular orbit(assumed) and this is happening in an isolated space in some ...
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Electric potential due to something

What is the diffrence between "electric potential at some point due something" and "electric potential of something" ?
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Determine potential function given initial conditions?

Assuming a radially symmetric circular disk (let's say r=1). Given two simple initial conditions: Potential at the centre is 4 V Potential at the edges is 0 V How would I determine the potential ...
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Why electric potential at equatorial point of a dipole is 0?

Well ok I know that electric potential at equatorial point of a dipole is 0. It is a derived conclusion. Q1. But how this can be explained "theoretically"? Another question that electric potential ...
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What does a voltmeter actually measure?

For time varying fields (even quasistatic ones) the electric field is given by $${\bf E} = - \nabla \Phi - \frac{\partial {\bf A}}{\partial t}$$ So what does a voltmeter measure? Does it measure a ...
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The Zero Electric Potential of the “Earth”

I know its the potential differences that matter and generally we define the zero of the electric potential according to our convenience. I would like you to look at this standard problem: Charge $-...
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Why do we use gauges in Maxwell equation?

While solving the Maxwell's equation we often use the Lorenz or Coulomb gauge, but why is that? Are the equations unsolvable if the gauge is not fixed? Or is it just for the simplicity?
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why does the Lennard-Jones potential fail to accurately describe forces between simple molecules, eg ammonia?

I have found only one reason, this being polarisation isn't accounted for. See for example this PDF - it is in the middle of the second paragraph, first page. What other reasons lead to the failure ...
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Under what condition is angular momentum conserved in both classical and quantum physics?

Classically, angular momentum is only conserved in a central potential by considering the torque (correct me if I am wrong). In quantum mechanics, it is also true, isn't it? If this is the case, ...
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Grounding system of conducting plates

So, I always make mistakes on problems such as this (the grounding part), so I'm hoping someone could really explain to me how the process works . There are n large parallel plate conductors carrying ...
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Why is resting membrane potential or a membrane depolarisation localised to the membrane?

Why would a membrane depolarisation be localised to one part of the membrane? If adjacent areas have a more negative potential shouldn't the difference in potential cause charge to flow into the ...
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Charging capacity and capacitance of a conductor

I know that charging capacity of a conductor is the maximum charge a conductor can hold And capacitance is the ability of a conductor to hold charge in a given potential . But how are these two ...
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Which is the form of Born-Mayer repulsion term?

I have found in many textbooks different and unclear form of the Born-Mayer repulsion term. I write the interatomic potential as $V(r)= -\frac{e^2}{r}+V_{BM}$ and for $V_{BM}$ I expected something ...
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De-merits of the application of Laplace's Equation to find electrostatics potentials

QUESTION: What are the de-merits of the application of Laplace's Equation to find electrostatics potentials? Our professor told us that the answer was as follows: It can be used only when the ...
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Why is the electric potential zero in this case?

The situation: a charge of $-2q$ is situated a distance $r$ to the left of a charge of $q$. What is the electric potential at a point $p$ a distance $r$ to the right of charge $q$? So basically: -2q -...
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Measuring potential

I apologize if the question below has been asked -- I could not find an answer. A charged conductor some distance above ground generates an electric field and corresponding potential profile. How ...
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Resistance from $I$-$V$ graph

I thought that the answer was obviously A as the gradient remains constant...however, the answer is B...who so?
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EMF or terminal voltage?

I have a doubt that is: What does this statement mean: "a 6 V battery". Does this mean that the EMF of the battery is 6 V or the terminal voltage of the battery is 6 V? If the battery has internal ...
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WKB Approximation on an linear + harmonic potential

I have a quick question: I have performed the WKB approximation to find the energies of bound states in symmetric potentials (Square, harmonic, ...). To do this I just find the "turning points" by ...
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Finding $\psi(0)$ using Schrodinger equation with potential $U(x) = q\delta(x)$

I am having some trouble answering the following question in my "Advanced Quantum Mechanics" course: Using the integral equation: $$\psi(x) = Ae^{ikx} + Be^{-ikx} - \int_{-\infty}^{\infty}G^{\pm}(...
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What does potential mean in capacitor?

Technically potential means work done to move a unit positive charge from one point to another against electrical field but What does potential mean in a capacitor?
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Where is the zero electric potential energy point?

Does the point of the electric potential energy of zero is defined by human or dominated by the indefinite integral of the electric force?
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Charge Magnitude Based on Isoline Spacing

Suppose we have two positive charges of unknown magnitudes. We are given the isoline map (the equipotential lines) for the two-charge system. One has isolines more "squashed together" (more closely ...
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Why is the energy shift due to a 'sagging' potential negative and independent of box size?

Consider a box of width $L$ and the composed of the following potential $$V(x)=\frac{V_0x(x-L)}{L^2}, x\in[0,L]$$ and $V(x)=\infty$ elsewhere. Using perturbation theory - with a square box as the ...
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What is the charge density for line and surface charges?

In electrostatics it is common to see line, surface and volumetric charges being described differently. A line distribution is a function defined on the line, a surface charge distribution is a ...
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What is the relationship between potential energy and electrical potential?

I actually always thought this was trivial, now I am not so sure. For a potential $\phi$ the potential energy is $V=q\phi$ where q is a test charge. Now I am thinking this may work differently in two ...
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Understanding electric potential in the context of gravitational potential?

I'm trying to understand the concept of electric potential and the significance of an electric field being related to the gradient/derivative of an electric potential. I found this question that ...
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What is the difference between length and velocity gauge when it comes to a dipole approximation?

Lets say we have plane wave with $\vec E$ perpendicular to $\vec k$. The dipole term will come from $\vec A\cdot \vec p$. Is the electric field longitudinal in the length gauge for the dipole ...
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What happens to the electric field at the boundary of a dielectric?

The question in the title is a broader one, but for now, I want to confine myself to the following problem. I have the task to find the potential difference between points A and B shown in the ...
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What is the difference between the potential difference and potential energy of an electron?

What is the difference between the potential difference and potential energy of an electron? Let's take an example the potential difference (PD) across a resistor. if there's a current flowing, the ...
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If the potential drops across a resistor (=$V_d$) then shouldn't the potential difference be the $\epsilon-V_d$?

Consider the following circuit: Suppose a current $I$ travels in both the branches, then as the current $I$ passes through the $60$ ohm resistor, there will be a drop in the potential of $60I$. ...