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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Electrostatic potential of a line charge? [closed]

The answer is C, But I don't know the concept or the method that is used to solve this problem. Could someone explain the concept in order to solve this type of problem?
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density and inertial mass

Water's density at 60-degree Fahrenheit is 62.366 pounds/ft^3. Is it inertial or gravitational mass? Actually, I am trying to calculate Potential Energy (PE) of 1 gallon of water at 1' height. Is PE = ...
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Is this a good description for potential energy?

The potential energy can be seen as the energy stored in a system that can be "expelled". An object at a height $h$ above its reference point has a potential energy given by $U_{gravitational} = mgh$. ...
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Assumptions in the equation Electric Potential ($V$)=$-\int\vec{E}\cdot d\vec{l}$

Electric Potential: $V=-\int\vec{E}\cdot d\vec{l}$ In this definition, do we have inbuilt assumption that test charge that we are moving is +ve and movement is against the field. Because depending ...
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Potential and Field for a sphere with a central core of differing density [closed]

A spherically symmetric planet of radius $a$ consists of a central core of radius $b(<a)$ of uniform density $\rho_1$ surrounded by an outer region of uniform density $\rho_2$. Obtain an expression ...
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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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299 views

Time dependent solution to infinite well

A particle of mass $m$ is confined within an infinite, one-dimensional potential well, $U(x)$, of width $a$. $$ U\left(x\right) = \left\{ \begin{array}{lr} \infty &\: x \leq \frac{-a}...
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Equipotential inside a conductor ring, but how do I determine the value?

I was mapping the potential lines of 2 cylindrical electrodes - one at 0 V, the other at 5 V. I have a metallic ring midway between the 2 electrodes. I know that the electric field inside the ring is ...
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How to simplify such structures to calculate equivalent capacitance?

I am self studying electrostatics for competetive examinations but there is this series of questions demanding equivalent capacitance and I direly need a intuitive understanding of these situations.
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Vector plus vector equals scalar ? (Nabla operator)

A quick question that is currently bothering me. I have the following equation: $\mathbf{E}+\frac{\partial \mathbf{A}}{\partial t} = -\nabla V$ My question is, how can the right side, being a ...
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What is the difference between electric potential and electric potential energy? [duplicate]

I am really confused between electric potential and electric potential energy. Please help me in understanding the two terms and also show the differences between them.
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Which number should I suppose to $a$ (width of well) and $m$ (mass of particle) in potential well problem? [closed]

I tried to plot a complete of state functions of potential well problem but graph was so weird. I thought a cause was variables a and ...
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If $\vec{F}=-\nabla V$ and $V ∝ 1/r^2$, then shouldn't objects fly up instead of fall down?

If the apple moves from the higher potential to lower potential $(\vec{F}=-\nabla V)$ and the closer the distance the higher potential $(V ∝ 1/r^2)$, then shouldn't the apple fly up instead of fall ...
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Energy of an electron in triangle potential [duplicate]

I'm trying to get the fundamental state of an electron in a potential, as in: $$V(X)=e|x|$$ Where $e$ is a constant. To start with I want to solve it with $e=1$, then where $e$ is big enough that it ...
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Why the equipotential surface of a uniform electric field can't intersect itself? [closed]

Why the equipotential surface of a uniform electric field can't intersect itself?
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What am I doing wrong? [closed]

This seems a rather simple question and I feel silly for asking it, but I don't know what I am doing wrong. On Earth a person is able to jump 1.5m. The person is now transported onto an asteroid ...
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The distance of closest approach [closed]

A point charge $+q$ is projected from a point $A$ towards an infinitely long line changes having linear charge density $\lambda$ with kinetic energy $k_0$.The distance of closest approach will be ...
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Can anyone explain the harmonic oscillator (in context to quantum mechanics) 2.3 (Griffiths) using Taylor series?

At the end he concludes $V(x) = V''(x_0)(x-x_0)^2$. How does he get to know that the rest are $0$? How does he conclude $V''(x_0) = k$. Please try to explain in easy ways and tough vocabulary. I don't ...
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How do I solve this Laplace equation? [closed]

I'm stuck with the following problem: Suppose we have an infinitely long box whose cross-section has a rectangular shape of dimensions 2×3. Take the four last digits of your student ID number as a ...
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How to calculate the potential and electric field everywhere if we know the electrostatic potential on the surface of a cylindrical? [closed]

I know that electric field $E=-∇V.$ But since the only given parameter is the potential on the surface. Is it possible to calculate the potential everywhere (positions besides the surface)?
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Definitive measurement of the correct “gravity potential difference” and uncertainty of its determination by “conventional measurement”

In this article (doi) describing recent experiments on "Geodesy and metrology with a transportable clock" featuring a "transportable Sr optical lattice clock" there is an interesting remark towards ...
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Vector potential from magnetic field

If a uniform magnetic field ${\bf{B}}=B_{z}{\bf{\hat{z}}}$ exists in a hollow cylinder (with the top and bottom open) with a radius $R$ and axis pointing in the $z$-direction, then the vector ...
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Acceleration due to gravity: what's the derivation? [closed]

Modelling the Earth as a symmetric, spherical body (and by using the law of gravitation), we come up with the equation $$w = F_g = \frac{Gm_Em}{R_E^2}$$ How do we arrive to the equation to get the ...
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Problem from Sakurai about a delta-function potential [closed]

Can you help me with this problem from Sakurai: A particle of mass m in one dimension is bound to a fixed center by an attractive delta-function potential: $$V(x) ~= ~-a\delta(x) , \qquad a>0.$$...
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Is there a minimum energy in the ground state of a particle in a finite square potential well? If yes then how to find it? [closed]

The equation can be given as: $\phi(x)=Ae^{\gamma x}$ for $x<-\frac {L} {2}$ $$\phi(x)=A \frac{e^{-\frac { \gamma L} {2}}}{\cos\left(\frac{kL}{2}\right)}\cos (kx)$$ for -$\frac {L}{2}<x< \...
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Given the parameters of the electrostatics problem, is this integral possible to evaluate analytically? [closed]

A cone with apex at the origin has a height $h$ and a top radius $h$, a uniform charge density with no charge on the top face. I need to find the potential $V$ at a position $z$ on the cone's axis ...
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1answer
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Which point has zero potential between equally charged parallel plates? Or, can we say the mid point is zero potential?

Which point has zero potential between equally charged parallel plates? Or, can we say the mid point is zero potential?
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Electrical potential of an infinite sheet

say we have a 2D sheet which stetches infinitely across $x$ and $y$ with a charge density σ. then at any point z above the sheet the electric field E is just the electric field in the z direction ...
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Why does this paper report potential energy in kHz, and what does it mean?

I am interested in studying theoretically the double well system shown in the figure below, which shows an experimental demonstration of an atomtronic battery. Caption: Figure 1. (a) ...
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How can current remain same when potential difference decreases?

According to Ohm's law, $$\text{potential difference} = \text{resistance}\times\text{current}$$ Also, current remains the same everywhere. Now when current passes through a bulb, the electric ...
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What is the formula of Coulomb potential?

According to "Lectures on Quantum Mechanics" by Steven Weinberg, the formula of Coulomb potential is $$V(r) = - \frac{Z e^2}{r}.$$ But it this true? I calculated the integral $$V = - \int _\infty ^...
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Deriving relation for gravitational self energy

My book says $U_{self}=\dfrac{-GM^2}{2R}$ for the hollow sphere, I tried deriving it as: Suppose mass constructed is $m$, Work done on bringing mass $dm$ from $\infty$ to $R$ is $$dW=dm(V_{R}-V_{\...
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Why is the electric potential on the surface of a sphere not infinite?

By using Gauss' Law, it can be shown that a uniformly charged hollow sphere can be treated as a point charge lying at its centre with a charge equal to that of the sphere. Owing to this fact, the ...
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Importance of the equations of Clebsh-Helmholtz

Reading the book Introduction to Electrodynamics 4th edition David J. Griffiths I read this: Reading it, and understanding it very little, because I find it logically unrelated to Maxwell's equations,...
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Delta function potential and continuity of the derivative

In Gasiorowicz Quantum Mechanics, 3rd ed, pg.81, he finds the bound states for a delta function potential the following way: I have the following delta potential: $V(x)=-\frac{\hbar^2\lambda}{2ma}\...
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Electric Field Topology in a Wire - Exact Duplicate [closed]

1. How is the electric field set up in a wire by a battery so that we can assume that potential at a node is constant? 2. What happens to the electric field across a resistance which makes voltage '...
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Is electron volt an alternate unit for electric potential? [closed]

My question is: Can an electron volt be considered an alternate unit for electric potential?
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Doesn't any massive conductor look like “ground” to an AC supply?

I've been puzzling over this excellent answer to the perennial "Why don't I get shocked by a hot wire if I'm not grounded?" question. The orders of magnitude just don't seem right for two reasons: ...
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If systems minimize their potential energy, why do people climb mountains? [closed]

A person climbs a mountain. They convert the stored chemical energy of food in their body and back pack into heat energy on the mountain, and gravitational potential energy as they move towards the ...
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Why airports are generally near sea? [closed]

The generic way to measure the height is from the sea-level. If the airport is near the sea i.e. not at a very height from the sea, then the fuel required to make the air-plane above the sea level ...
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Lennard-Jones potential - equilibrium [closed]

If I have Lennard-Jones potential, how can I calculate equilibrium? $$ U(r)=\epsilon \left ( \left (\frac{r_m}{r} \right )^{12}-2 \left (\frac{r_m}{r}\right )^6 \right ) \ $$