For questions that utilize the concept of electric fields (commonly denoted by the letter E), or for questions whose answers likely involve electric fields. More specific than the [tag:electricity], as questions about the phenomenon & theory of electricity do not necessarily involve the discussion ...

learn more… | top users | synonyms (1)

0
votes
2answers
17 views

Determination of the electric field of charged object using Gauss's law

when we determine the electric field of a charged rod of infinite length,we consider a circular cylinder to be the gaussian surface for convenience.In the case of a charged sheet we choose the ...
-1
votes
0answers
19 views

Particles A and B have different masses and net electric charges [on hold]

is the size of the electric force on particle A due to particle B the same as that on B due to A??
1
vote
1answer
58 views

Electric flux of a charged rod through a uniform disc

I have an assignment regarding electric flux. The question I was given has the following sketch: The first question was about the force on the rod from the disc at the $z$-axis. I reached the ...
2
votes
1answer
53 views

Does changing a closed surface in the manner outlined contradict Gauss' Law?

As I understand it, Gauss' Law states that the electric flux on any arbitrary closed surface is equivalent to the sum of all charges enclosed within the surface times a constant. Mathematically, this ...
4
votes
2answers
234 views

Electric Field inside a diode

When a voltage is applied to a diode (Forward or Reversed bias) the depletion zone is changed due to charges change in this region. My question is in both case (Forward or Reversed bias), how the ...
1
vote
0answers
33 views

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 ...
-2
votes
3answers
106 views

Composition of energy of electron? [closed]

Mass energy of electron is 0.510 998 9461MeV/ c2 1) Does it include energy of electron due to electric field too? 2) If yes, how much? I am more interested in second part. Links:Here John Rennie ...
-1
votes
0answers
26 views

Charged particle in rest frame and their magnetic field [on hold]

I’m wondering how statements like "A charged particle at rest creates an electric field, but no magnetic field" are right. An electron has an electric field and it has a magnetic dipole moment. Both ...
0
votes
1answer
726 views

Calculating voltage in piezoelectric material

The piezoelectric constitutive law is defined by the two equations: $$S=s T+dE\\ D=d T+\epsilon E$$ $S$: Strain. $T$: Stress. $E$: Electric field. $D$: electric charge-density displacement. ...
0
votes
1answer
28 views

Electric field inside an insulator's cavity [on hold]

I'm trying to find the electric field inside insulating sphere's cavity, and I don't know how. However, if there was an conductor I'd know that $E=0$ from Gauss's Law.
-1
votes
2answers
34 views

Electric fields with different frequencies, total intensity?

What happens when electric fields with different frequencies are combined? Is it possible to calculate the intensity of the total electric field? For a project, I need to simulate a brain treated ...
0
votes
1answer
159 views

Effect of a dielectric medium on electric field and electric flux

What is the effect of dielectric medium in comparison to vacuum on electric field and electric flux. I read that higher dielectric constant means higher relative permittivity which means more ...
1
vote
2answers
178 views

Microscopic fields inside a conductor

In a neutral conductor if we assume electrons as point charges, the electric field in the space between them cannot be identically zero. This microscopic field may be very weak. What if we were very ...
2
votes
1answer
72 views

Electric field due to a time and space varying current density?

Let us say I have a current density: $$\vec J\equiv\vec J(\vec r, t)$$ This will produce both a time varying magnetic field and a net charge density. Both these effects produce an electric field. If ...
2
votes
0answers
27 views

What is the meaning of the Fourier Transform of the electric field of a well guided mode in a dielectric waveguide?

I have been studying waveguiding in dielectrics for a while now; however, I cannot understand the meaning of the Fourier transformed electric field. I will first give some background information. ...
0
votes
2answers
38 views

Zero electric field in empty region of hollow conductor

A hollow conducting shell having a net charge of +Q has a point charge -Q placed at its centre. From the diagram, it looks like Suppose the radius of the inner shell from the origin is a and the ...
0
votes
0answers
20 views

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 ...
0
votes
1answer
21 views

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 ...
0
votes
1answer
21 views

Finding the maximum magnitude of an electric field?

I'm working on a lab report on electric fields and I need to calculate the magnitude of the maximum electric field given by the formula $E= ∆φ/∆s, $ where ∆φ is the change in ...
0
votes
2answers
50 views

Is Kirchhoff's Law Applicable for non-conservative electric field?

The question title sums it up pretty well, but to elaborate, is Kirchhoff's Law valid for situations where the emf is due to non-conservative electric field, like one produced due to a varying ...
1
vote
3answers
110 views

How does the Electric Field create a force? [closed]

If we have 2 charged particles which are a certain distance away from each other, they either attract of repel due to the electric field created by both of them. But I don't understand the mechanism ...
0
votes
0answers
20 views

Electric field of an infinite plane (with and without an infinite conductor)

Suppose we have an infinite and uniformly charged (of surface charge density $\sigma \gt 0$) plane at $z = 0$. We can find the electric field at any point $(x, y, z)$ by computing an integral all ...
0
votes
1answer
30 views

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?
-1
votes
1answer
27 views

Electrostatics, System of Charges [closed]

At $t=0$, a positive point charge of mass $m$ is projected toward another positive point charge of mass $m$ in free space. At the instant of minimum separation kinetic energy of the system of two ...
4
votes
1answer
677 views

Why are atomic quadrupole moments calculated using nuclear spin?

It's my understanding that electric quadrupoles interact with the gradient of an electric field, and I understand roughly how this works. I am trying to calculate the interaction between an atomic ...
-1
votes
1answer
53 views

Integrating by parts [closed]

I am having little trouble with my professor's note. $$F=-\int{(dr)}{(\vec{\nabla} \cdot \vec{P}) \vec{E} }=\int{(dr)}{(\vec{P} \cdot \vec{\nabla} ) \vec{E} }$$ where F is force, P is polarization, ...
4
votes
2answers
93 views

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 ...
0
votes
2answers
35 views

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 ...
1
vote
1answer
141 views

Is it possible to create arbitrary shapes of magnetic fields?

I've been reading about Transcranial Magnetic Stimulation (TMS) which can activate neurons using a magnetic field, which got me thinking... what if we can pick and choose exactly which neurons to ...
0
votes
1answer
27 views

Finding the electric field in a bar moving through a magnetic field [closed]

In this diagram: I'm supposed to find the electric field through the bar at equilibrium. I know that at equilibrium, the accumulated positive charge on the bottom of the bar results in a field that ...
0
votes
1answer
13 views

Methods to ioniz air molecules

What are other alternatives ways to ionize air molecules, except the electric field charging and the use of the so-called corona discharge?
0
votes
2answers
60 views

What is beyond Gamma Rays and Radiowaves in the Electromagnetic Spectrum?

The electromagnetic spectrum is commonly refered to as consisting of; Radio-waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, Gamma Rays - of increasing frequency from left to right. ...
0
votes
2answers
36 views

electrical field in coaxial cable

When getting the electric field between the outer and inner cylinder. why is it that we are only concerned with the field generated by the positive charge distribution on the inner surface and not ...
8
votes
5answers
491 views

Can one deduce absolute motion through magnetism? [closed]

I am trying to understand forces in relativity: Suppose there are two electrons A , B travelling side by side at 1 cm distance at .99 c (in space or at lHC, ignoring all other factors). I know that ...
0
votes
1answer
30 views

Why is the electric field homogenous inside a circuit?

In a circuit between to poles of a battery, there is an electric field accelerating the charges in the wire towards lower potencial (but due to resistivity they only travel at drift velocity). Is ...
1
vote
3answers
66 views

how could Kinetic energy increase if no energy was there in the system?

i was reading Physics-Halliday, Resnick, Krane(fifth edition) there on page 638 it is written: if the external agent does positive work in assembling the charge ...
0
votes
0answers
23 views

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 ...
1
vote
0answers
21 views

Reversibility of uniqueness theorem

If we use uniqueness theorem then we know that if the boundary conditions and the charge distribution is same in 2 setups in a certain region then the electric field and potential in that region in ...
3
votes
3answers
281 views

Difference between $E$ field configuration, sheet of charge: infinite sheet of charge, conducting vs. non-conducting

This is a very easy question, but I often confused myself. Perhaps someone could explain this concept again: A non-conducting infinite sheet of charge has the electric field configuration ...
0
votes
1answer
25 views

Understanding zero field inside a conductor?

Imagine a neutral conductor of any shape, the charges are randomly distribuited among the object. No way we can say the electric field inside is zero. If I'm wrong, then what can we say about the ...
0
votes
0answers
16 views

Which way does the force due to current point

The current is towards the right. The particle with charge $-q$ is going with velocity towards the right. How does one find the force due to the current on $-q$? (The RHR doesn't do anything here). ...
2
votes
1answer
266 views

Electric field in space created by intersection of spheres of charge [closed]

I am trying to calculate the electric field in space created by a body assembled by the intersection of 2 spheres. The upper sphere, its center is at $$\frac{d}{2}\mathbf{\hat{z}}$$ with radius $R$ ...
0
votes
1answer
60 views

Motion of an electron in a magnetic and electric field [closed]

I have this problem where i should find the direction and magnitude of the electric and the magnetic force on the electron. E = 1000 N/C B = 2,5 T v = 500 m/s ...
0
votes
1answer
152 views

How can electric field representation be obtained from Enge representation using Maxwell's equations?

Suppose we have a long electric capacitor. Let $L$ be its length ($z$ coordinate), $W$ its width ($y$ coordinate), and $D$ its full height (full aperture; $x$ coordinate). Let $L\gg W\gg D$. The ...
0
votes
3answers
36 views

Understanding Capacitors [duplicate]

I cannot understand how capacitors work. Electric field is supposedly uniform between the parallel plates of a capacitor. But how? Since $E=\frac{kq}{d^2}$, shouldn't the electric field approach ...
4
votes
1answer
391 views

What factors cause the velocity saturation to occur at different electric fields for different materials?

In semiconductors the velocity of carriers gets saturated after a certain value of electric field. In silicon it occurs at around $10^4 kV/cm$ and in GaAs at some other value. What factors are ...
2
votes
3answers
388 views

Why does the Electric Field of a dipole have no $x$ component?

According to the solution $2E\sin(\theta) = E_{net}$. I understand how the dipole works but I don't understand why the x component would be 0?
0
votes
1answer
41 views

electron in magnetic and electric field

I have this problem where i should find the direction and magnitude of the electric and the magnetic force on the electron. And then I'm supposed to find the direction and magnitude of the ...
0
votes
1answer
322 views

Why does a point charge generate an electric field and why is an electric field represented by this formula?

Why does a point charge generate an electric field and why is an electric field represented by this formula $$E ~=~ \frac{q}{4 \pi \epsilon r^2},$$ where $\epsilon$ is permittivity of free space ...
2
votes
3answers
197 views

Static electricty and fields inside of the conductor?

I have a few related questions about static electricity and conductors. 1. when we say static electric field inside a conductor is zero, let us take an example of two concentric conductors, outer one ...