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 ...

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1answer
109 views

Electric flux density for a hollow cylinder using Gauss's law [closed]

In the textbook of "Engineering Electromagnetics": I understood it except the part highlighted with yellow(i.e. how did he find the charge distribution of the outer cylinder? What are the ...
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3answers
132 views

What would be the capacitance of an unequal charged capacitor?

I searched for this question but I cannot get satisfactory answer. Say if we have a parallel plate or cylindrical capacitor and if I supply unequal charge to it how could I find its Capacitance. We ...
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0answers
105 views

Electric field due to charged disc, on the plane of the disc [closed]

A standard problem in finding the field is that of a uniformly charged disc, on its axis, but for this problem I'm supposed to find the potential and the field on the edge of the disc, i.e. in the ...
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1answer
117 views

Why is electric flux zero if my point charge is outside of a sphere? [duplicate]

I am currently studying Gauss Law and Electric flux , during one of my exercises they ask me to find the electric flux of a sphere with radius 5 cm and my point charge is 10 cm to the left of the ...
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1answer
200 views

How in detail the rotation of the electric field component of light during transition through a polarizer takes place?

I ask "After a slit, are photons polarized?" and later found two answers for the question "Why does the electric field dominate in light?". From this two answers I have concluded or summarized, that ...
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1answer
148 views

Electric field of a Uniformly charged sphere with a cavity [closed]

I have the following question: Consider a sphere of radius $R$, uniformly charged with a volume density $\rho$. The sphere has a spherical hole of radius $R/4$ at a distance $R/2$ from the ...
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0answers
34 views

Strongly Influencing Electric & Magnetic Field Forces:

Why is it easier to block electric field forces than magnetic field forces in close ranges to the source? What is the best way to block, redirect, and minimize the strength of half of the lines of ...
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1answer
32 views

If I pass light through a conducting ring will I get an emf induced in the ring? Also if I do get an emf would that not violate energy conservation?

Here is what I think should happen. Light being an electromagnetic wave should have an oscillating magnetic component which should constantly change the flux linked with the conductor. Hence an emf ...
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0answers
26 views

Fréedericksz transition question

What is the lowest voltage needed for a Fréedericksz transition to occur?
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0answers
22 views

E field inside wires during transient state

I've come across an instructive paper which explains qualitatively what happens inside wires of a simple circuit during the transient state, leading to the steady state where there is an uniform E ...
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0answers
54 views

Electric field of a dipole in cartesian

I have the function that describes the electric field of a dipole in cartesian coordinates: $$E_z= \frac{p}{4\pi\epsilon_0} \cdot \left(\frac{3z^2}{r^5}- \frac{1}{r^3}\right) $$ and $$E_x=\frac{p}{4\...
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1answer
43 views

Is electric potential a field?

I'm just learning about electric potential in my second-semester physics class. My textbook is emphasizing the fact that electric potential is a property of the source charges and that I'll soon learn ...
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2answers
700 views

Principle behind electrostatic shielding?

If we have a solid conducting sphere with charges around it, then the electric field inside the sphere is zero, otherwise the electrons of the sphere would not be in equilibrium as there would be a ...
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0answers
51 views

Two spheres (one positive, one negative) - electric field

I posted yesterday about a problem I had and I have managed to solve one of the two I think (Here is the original post: Dielectric field in a homogenous electric field ). I didn't want to edit the ...
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0answers
42 views

Dielectric field in a homogenous electric field

I'm working through my workbook right now and currently am stuck on the chapter about dielectrics. The term $\vec{E}=\frac{3}{\epsilon_r +2}\vec{E_0}$ was introduced without a proper proof. Instead ...
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3answers
77 views

How can one produce a projected electric field? [closed]

Original question: How can one produce an electric field? I understand that there is a method involving metal sheets and running an electrical current through the parallel sheets. However, is there a ...
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3answers
194 views

Can pulsating DC current be transformed?

Since pulsating DC current is changing, why doesn't it induce a changing magnetic flux in the transformer core? Is it able to induce a transformed current in the secondary coil?
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1answer
190 views

Electric field inside coaxial cable

I have a very long coaxial cable with a cylindrical core of radius $a$ that has negative charge density $\rho = -k/r$ where $r$ is the distance from the axis of the cylinder, and an outer shell of ...
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1answer
198 views

What is wavelength of electric field generated in a wire? [closed]

I read link given below: http://en.wikipedia.org/wiki/Speed_of_electricity Above link says _The speed at which energy or signals travel down a cable is actually the speed of the electromagnetic ...
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1answer
69 views

How the infinite electric field of an electron goes through a slit? [closed]

An electron is an indivisible particle and its electric field has to be a constant too. Going through a slit how the electric field goes through the wall and how it will be regenerated behind the slit?...
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0answers
46 views

What is the largest distance for which the influence of the electric field of a single electron was measured?

I suppose that Rydberg atoms are the best way to find by experiments the largest distance of influence of the electric field of a single electron in a electric dipole. Furthermore how the electrical ...
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1answer
45 views

Where does the net charge on a hemisphere appear to act from?

I was wondering if, like centre of mass, there is anything called "centre of charge".
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2answers
125 views

In a circuit one light-second long, does it matter where in the circuit the switch is placed? [duplicate]

I was looking at this textbook example that was posted to reddit: The accompanying comments basically thrashed it saying everything was wrong. I had a specific question about it, though, and this ...
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1answer
191 views

Why does an electromagnet attract iron according to Special Relativity?

I saw a video of Veritasium on "How Special Relativity Makes Magnets Work" and came up with a question. So please watch the video first before answering my question as it is related to the video. 1) ...
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2answers
95 views

Electric field and electric scalar potential of two perpendicular wires

So, I've been trying to come up with an idea that seems plausible to me for the last half week or so, but I'm stuck and I can't seem to get anywhere with this problem. The problem is as follows (...
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2answers
134 views

Where does a straight conducting wire get its capacitance?

If I take a simple piece of conducting wire (of which I can calculate the resistance from the wire dimensions and resistivity of the wire material) and connect it across the terminals of a battery of ...
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0answers
69 views

Distance of the electric field generated by a Slayer Exciter ( Variation of tesla coil )

I'm currently trying to create a really basic simulation of a slayer exciter for a demonstration I have to give at my college. The thing is we want to know how far does the electric field produced by ...
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1answer
17 views

Find Electric Field at certain radii for a sphere

If radius of non-conducting sphere is R=4cm, find Electric field at r1=3 cm (for inner Gaussian surface) and r2=6cm(for outer Gaussian surface) Volume charge density is given as: ρ = c r^2 where c ...
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1answer
112 views

How is magnetic field created in an atom according to quantum model

How is magnetic field created in an atom according to quantum model? I mean, we are taught about the magnetic field by bohr's model which assumes that electron revolves around the nucleus in a ...
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0answers
92 views

Potential vs Potential Difference for a line charge

How would I calculate potential for an infinite line of charge a distance 'r' away from it? What does the reference point for potential difference mean? I know delta v = Q/(2pi*epsilon0*L)*ln(r2/r1) ...
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2answers
71 views

Parallel Connection of Capacitor

Assume Two Capacitor filled with different dielectrics with dielectric constant $K_1$ and $K_2$ respectively in Parallel connection. Then we have same voltage $V$ on both capacitors. Therefore, $$\...
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1answer
88 views

Work done by Electric Field vs work done by outside force

I'm confused as to the signage of the equation: W=qv, W=-U, W=-qv? When is work positive? When is it negative? Why is this different for the work done by the electric field vs the work done by an ...
4
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1answer
58 views

Why do these calculations of EM fields for a magnet and wire loop seem inconsistent?

Suppose you have a conducting circular wire loop and a magnet moving towards each other. They move along the $z$ direction with nonrelativistic constant speed $v$. Let the $B$ field of the magnet in ...
2
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1answer
72 views

Why a motionless proton doesn't feel any force in a magnetic field according to special relativity?

In this ( https://www.youtube.com/watch?v=1TKSfAkWWN0 ) specific video uploaded by Veritasium on YOUTUBE , we come to know about how special relativity makes magnets work. We observe that when a ...
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1answer
42 views

How soon would electrons start flowing once I closed a switch on a circuit that was one light minute away from the battery

In a circuit, how do electrons "know" when the circuit is closed? To my understanding, they do not start flowing unless the circuit is closed. How soon would they start flowing once I closed a ...
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1answer
25 views

Intersection of electric field lines where the two lines have the same slope at intersection

We know that the electric field lines cannot intersect in this way: But what about this way?(where the two lines have the same slope at the point where they touch) : Could the second situation ...
0
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1answer
105 views

Two capacitors in parallel vs series - electric field?

If we have two parallel plate capacitors in parallel, do the electric fields between their plates have to be the same? What happens if we have a coaxial cable of length $L$, which looks like this: ...
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0answers
14 views

Generation of negative ions in air [duplicate]

What is the main physical mechanism behind the generation of negative ions in air by a high negative voltage electrode ?
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1answer
74 views

Electric and magnetic fields with synchrotrons

Can anyone describe to me one change to the electric field and one change to the magnetic field that MUST take place as particles gains energy in a synchrotron accelerator? This could also just be an ...
0
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1answer
80 views

Electric field at $r=0$

How does classical physics justify the existence of an electric field at $r=0$? Is this an edge case, an ambiguity, a "does not exist"? Is this a trivial case or indicative of an actual fault in ...
0
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1answer
279 views

Electric Potential for Concentric Spherical Shells

If you have a charged point ($q_1=+1$) inside an initially neutral spherical shell ($q_2=0$), how would you find the following: (A) Potential at the outer surface of the spherical shell? Would it be ...
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0answers
91 views

Electric Potential for concentric spheres and charged surface

A few conceptual questions about a charged sphere inside an initially neutral spherical shell and about uniform E for a charged plane. (A) How would I go about calculating potential at a certain point ...
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1answer
70 views

Can an electric field help generate a current?

What i know or am guessing:- A moving/changing magnetic field creates an electric field. So if we take a rotating magnet near a coil of copper wire, it will induce a current right. So it means an ...
2
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1answer
342 views

Electric field for concentric spheres

I have a couple clarifying questions: (A) in $E=kq/r^2$ for the area between a sphere inside another spherical shell, the sphere inside is considered a point charge. However, the sphere inside has a ...
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0answers
29 views

How do you solve for flux density when you are given the E(x,y,z) and relative permittivity as a tensor?

This given material is not isotropic therefore the relative permittivity is represented as a tensor given by the matrix: $$\left(\begin{matrix} 3 & 1 & 2 \\ 2 & 3 & 3 \\ 2 & 2 &...
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1answer
28 views

Is it possible to consider loops that cut through charges when proving electric field is conservative?

My goal is to prove that the integral of E.dl along the blue curve is zero. My problem is shouldn't E field approach a discontinuity when approaching the plate? Even if we consider say a point charge ...
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1answer
46 views

Why in this problem I had to take the average of the electric field?

On an electrically charged soap bubble, acts an electric force outwards. We are given the total charge of the bubble, $Q$, and its radius, $R$. What is the value of the total force, acting to move ...
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1answer
38 views

Electric field and electric potential

I have a question about electric field inside hollow spherical conductor. I think I understand the concept of Faraday Cage that protect the cavity to get any electric field from an external source. ...
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1answer
235 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 ...
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1answer
315 views

Induced emf vs Potential difference

Let a square conductor frame length l, resistance R,be pulled out with a constant velocity v from a magnetic field B perpendicular to plane of the frame .Then an emf e=Blv is produced across the frame....