All Questions
Tagged with electromagnetism potential-energy
30
questions with no upvoted or accepted answers
3
votes
0
answers
53
views
A question regarding Coulomb sum in two dimension
The following arguments can be found in texts about Laughlin's wavefunction and theta function such as Laughlin's paper "Spin hamiltonian for which quantum hall wavefunction is exact". It is ...
- 51
2
votes
0
answers
429
views
Question about defining potential energy of a magnetic dipole placed in a magnetic field
We know that magnetic field is a non-conservative field, since it exists in closed loops.
Then how can we define the potential energy of a magnetic dipole placed in a magnetic field ?
- 291
2
votes
0
answers
2k
views
What is the minimum physical distance between two electrons?
If electrons repel, then it seems to me that energy is required to decrease the distance between two electrons. Since energy and mass are equivalent, adding energy to a system also adds some mass. ...
- 151
1
vote
1
answer
122
views
The (electrostatic) force on an extended object
It is well known that, if I have a system of $N$ particles acted upon only by conservative internal and external forces, then I can obtain the force on the $\mathrm{i^{th}}$ particle as
$$\textbf{F}_i ...
- 1,095
1
vote
2
answers
185
views
How is the total energy conserved when an electron moves through a plate capacitor and gets accelerated?
We assume that the electron enters the plate capacitor with a constant velocity. If we also assume that the electric field is homogeneous and edge effects can be neglected, a force along the y-axis ...
- 47
1
vote
1
answer
38
views
Cyclotron: why is there no work during the polarity shift?
From what I understand, the point of cyclotrons is to accelerate charges without requiring a huge potential difference: e.g. to accelerate a proton to 10 MeV, instead of using a single 10-megavolt ...
- 1,138
1
vote
0
answers
44
views
What's the potential energy in a system of magnets?
I am trying to model a 3d pendulum consisting of a magnetic bob attached to a string. If the pendulum is allowed to swing over a structure of permanent magnets, it will display complex motion (here a ...
- 91
1
vote
2
answers
534
views
Source of magnetic dipole potential energy
One of the basic expression that goes without much thinking is the potential energy expression of a magnetic dipole in a magnetic field, $$ U = -\mu\cdot B $$
In the case of electric and gravitational ...
1
vote
0
answers
27
views
How can I find the potential energy and force between a steel sphere and a magnet?
I'm fine with certain simplifying assumptions being made, I currently only know high-school level physics (the simpler the better). Also, if anyone can explain the intuition behind formulae, I would ...
1
vote
0
answers
60
views
What happens to the potential energy of an electric circuit during a voltage drop?
Is it accurate to say $$ W=\int{Fdx}=\int{EQdx}=\int{\frac{dV}{dx}Qdx}=QV$$
so voltage is like g*h it is a potential field and charge is like mass. We know that the energy flux(vector) is given by the ...
- 861
1
vote
1
answer
456
views
Potential Drop across Inductor VS Potential drop across Rotating coils in $B$-Field
I was trying to understand the difference between the Back emf generated across Inductor due to change in current and Back Emf Generated across a coil that is rotating in presence of B Field.
...
- 273
1
vote
0
answers
527
views
Particle in electromagnetic field Lagrangian
Given the two definitions of $\vec E$ and $\vec B$ by scalar potential $\phi$ and vector potential $\vec A$:
$$\vec B=\vec \nabla \times \vec A$$
$$\vec E=-\vec \nabla \phi -\frac 1 c\frac {\partial \...
- 141
1
vote
2
answers
74
views
Electric potential concept
Imagine having two charged plates, one positive and one negative, and a negative point charge is placed at the negative plate. Let's set the negative plate to zero potential. The distance between the ...
1
vote
0
answers
25
views
Proportionality of distance to work in differing conditions
Why is Work done by $F_{grav}$ and EMF proportional to distance but work done by $F_{elastic}$ proportional to the square of the distance?
- 343
1
vote
1
answer
81
views
Mass-Energy equivalence in case of minimal coupling
The energy-momentum relation of a free particle is (in SI Units):
$$
m^2c^4 =- c^2 \vec{p}^2 + E^2
$$
Minimal coupling is a way to fix a gauge freedom for the choice of canonical momentum (which I ...
- 6,763