5 votes

Simulator for trajectories of charged particles in electric fields?

You may have a look at agros2d which could simulate electrostatic fields determined by various boundary conditions and then charged particles in the electric field. A similar case as you mentioned in ...
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  • 2,078
5 votes

Simulator for trajectories of charged particles in electric fields?

Simion Directly from the product website: SIMION is a software package primarily used to calculate electric fields and the trajectories of charged particles in those fields when given a ...
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5 votes
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Contravariance and covariance of vectors

That's because you're using the 'fake' version of gradient. The true version for a scalar field $F$ is given as: $$ (\nabla F)= \frac{\partial F}{\partial Z^i } e^i$$ Here $e^i$ is the dual basis and ...
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4 votes
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Is Farady's law valid for conducting loop only?

Faraday's law is for a mathematical loop, even with nothing there.
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3 votes

What happens inside a conducting wire if it is placed in an electric field?

If the field is static, the conductor will be equipotential in the equilibrium state. If you bring the conductor in the field from a region with no field or with a different value of the field there ...
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  • 6,345
3 votes

Why Does an Electric Field Arise In This Situation?

The problem lies in the measurement method, not in the medium itself. As soon as you connect the battery, you will always have an electric field (actually also if you do not connect the battery), no ...
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  • 7,114
3 votes

Is energy infinite in an electric field?

"Can move it an infinite distance" is no way to measure energy. Give an object any amount of kinetic energy, and in the presence of no other forces, It will move an infinite distance. $\int_{...
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  • 3,764
3 votes
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Gauss' law in the presence of surface charges

There are two ways of explaining this. First is that if you're considering a charge density which is concentrated on a surface, then the electric field $\mathbf{E}$ does not satisfy the hypotheses of ...
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  • 2,502
2 votes
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Why doesn't the EM field above the center of a charged current loop look like a bivector?

First remark, the fields are along $z$ only when you stay on the axis due to symmetry considerations. In general however, the magnetic field will curve around the loop and the electric field will ...
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  • 1,182
2 votes

Why can't electric field by a single charge be at an angle?

Op has been getting several answers which may be correct but appear to be above the level of what OP was looking for. So I am taking a simpler approach. Consider the following diagram where we observe ...
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  • 2,175
2 votes

Why can't electric field by a single charge be at an angle?

At an angle to what? If you are imagining a point charge, it’s a coordinate singularity. If you stand at the North Pole, every direction is “south.” If you have an object which really has zero size,...
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2 votes

For the interface between two linear, isotropic, homogeneous dielectric materials with no free charge, does $E$ remain continuous?

No, if the permittivities are different. The relevant boundary condition is the continuity of the normal component of $\vec D$. For linear and isotropic media, this means that the relation between the ...
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  • 7,267
2 votes
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AP Physics: Continuity of electric potential for an infinite sheet

I think there is a good conceptual question here. I'm going to try to pitch this explanation at a level that is probably slightly higher than what is covered in AP Physics C, but that hopefully you ...
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2 votes

Fault/Technicalities with poynting theorem

Poynting's theorem assumes that expressions such as $\mathbf j \cdot \mathbf E$ and $\int E^2 dV$ are meaningful. When there is charge concentrated to a line or to a point, this is not the case in the ...
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2 votes

Flux through faces of cube if charge is placed at an edge-center

Hint : In general the flux through an oriented open or closed surface $\:\mathrm{S}\:$ due to a point charge $\:Q\:$ is \begin{equation} \Phi_{\mathrm{S}}=\dfrac{\Theta}{4\pi}\dfrac{Q}{\epsilon_{0}} \...
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2 votes

Why Does an Electric Field Arise In This Situation?

Water conducts electricity, so the battery drives a steady current through the water. There is therefore a current desity $$ {\bf j}= \sigma {\bf E}= - \sigma \nabla \phi$ $$ where $\sigma$ is the ...
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2 votes

How does parity work for the electric field and electric dipole and electric quadrapole transitions?

The electric quadrupole operator is quadratic in position: $$ Q_{jk}^{(i \rightarrow f)} = \langle i|r_jr_k-\frac 1 3 r^2\delta_{jk}|f\rangle$$ so it's even.
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2 votes
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Why charges does not move through the conductor here if potential at both ends of wire is same?

The electric field inside the conducting wire is zero due to electron rearrangement BUT the potential on each individual sphere is not zero, the difference is zero, and the NET current is zero, so the ...
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2 votes
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What is the signal velocity in a very thin enameled magnet wire?

In theory, for a straight wire in empty space, the TEM mode centered on the wire has only finite energy in the insulation, but infinite energy outside. The insulation thus has no effect on the wave ...
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1 vote
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What, precisely, using mathematics, is meant by "electric field with only an $\hat{x}$ component"?

A lot of three dimensional situations can be confusing. In general an electric field might vary across all three dimensions but in this case you are told that it does not vary with position (x,y) and ...
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Does charge always reside at the edge of a conductor's surface

The charges repel so they "want to" get as far from each other as possible. So they won't stay in the middle of the sheet but will distribute. A stable configuration is such that minimizes ...
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1 vote

Does a change in electric field cause a change in magnetic field, or do both just always happen together?

You are correct within the variant of EM theory where all fields are retarded, i.e. they are mathematically determined by state of some accelerated charge somewhere sometime in the past. However, ...
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1 vote

Voltage and electric field in a closed circuit confusion

It seems intuitive to think that to keep the electrons moving, the electric field must act everywhere in the circuit (1). You have to realize this intuition is like the intuition that in order for ...
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1 vote

Voltage and electric field in a closed circuit confusion

What is wrong here? You aren't thinking about what the "ideal wire" model is simplifying. The real wire has a small resistance. Maybe a few milliohms. And so there is a small electric field ...
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1 vote

Will a surface perpendicular to the electric field always be equipotential

In the case of electrostatic fields indeed equipotential surfaces are perpendicular to the electric field. In other cases the vector potential should also be considered.
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1 vote
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Distribution of Charges on a Conducting Cup

It is not strictly true that there is no charge on the inner surface. Note that as far as the field/charge is concerned, there is no abrubt transition between the outer surface and the inner surface, ...
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  • 7,267
1 vote
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Does electric current flow from higher potential to lower potential or from higher potential energy to lower potential energy?

Electric fields exert forces on charges. The charges then respond to these forces according to Newton’s laws. Suppose you have two objects with charges $q_1\neq q_2$ and masses $m_1\neq m_2$, ...
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  • 70.2k
1 vote

Capacitance of caapcitor with complex dielectric material

Instead of using the concept of capacitance of the medium, use the concept of elastance, which is the reciprocal of the capacitance: $S = 1/C$. In particular, for several capacitors in series, their ...
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1 vote

What is the electric field and potential inside and outside grounded conducting and non grounded conducting sphere?

The conducting sphere is a Faraday cage: The field inside it is zero. What does the grounding do for that? Nothing! Remember that the electric field is the gradient of the potential and does not ...
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1 vote

What would be the outcomes in this arrangement? would potential varies along a conducting wire?

Assuming the the sphere separation is large enough that the surface charge densities remain spherical, and assuming that charges from the wire do not significantly change that distribution, then ...
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