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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What is the total energy stored in lattice of point charges?

I am wondering if there is an equation that describes the the total energy stored in lattice of point charges? I know I calculate it by summing up the energies of all the individual charges but I am ...
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1answer
19 views

Eletric field on a semi circular ring, different charges on each quarter of a ring

In this image to calculate the net eletric field is used integration from 60 degrees to -60 degrees. Ok for me by now. But then I was doing this question, number 26: And he solves by doing that: ...
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1answer
23 views

Help with this question (Eletric Fields, Dipole) [on hold]

The answer in the textbook in the solutions manual is the following: I didn't undestand the last step. He said he did a binomial expansion, I just can't figure out! Appreciate any help.
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1answer
26 views

Is it possible for a conductor initially, not to have a charge?

Well I'm confused. The thing that was implanted to me is that when I hear about conductors, some charge is present and it can move freely. Now what I want to know is that is it possible for a ...
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2answers
91 views

Why do charged objects attract pieces of paper, but not pieces of metal?

I do not understand one concept in Physics: why charged objects (eg. a charged rod or comb) attract pieces of paper when brought close to them, but do not attract pieces of metal. I know that the ...
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9 views

Calculating the Electric Field at the center of an arc [closed]

A total charge Q is uniformly distributed on a 180º arc of thin, non-conducting rod in a semicircular arrangement with radius a. Calculate the electric field at the center of the arc. I'm not sure ...
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1answer
34 views

How to divide areas in electric field lines based on field strength?

A negative charge is surrounded by four positive charges. They are all of the same strength. The electric field lines are plotted below. I am looking for the property of the drawn 'red lines' that ...
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1answer
47 views

In the case of two equally charged particles, is the electric field between them incompressible?

When approach two electrons (or two protons or ...), the electric fields do not merge and stay isolated from each other. Which I borrowed from here. Is it right to conclude that in the case of ...
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4answers
128 views

Why does not a battery kept in empty space discharge on its own? If space between the terminals is empty, what prevents the electrons to flow?

Given here is the picture of a twisted battery kept in free space (vacuum). Will the battery discharge quickly? I mean, it should discharge faster than it would if we were to connect the terminals ...
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5answers
44 views

Flux of $E$ through the shaded side

A charge $q$ sits at the back corner of a cube, as shown in Figure. What is the flux of $E$ through the shaded side? One of the solution stated that. Looking at the figure, we notice two ...
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0answers
32 views

Electric field through closed glass tube

I have two electrodes outside a closed fused quartz glass tube. The tube is a cylinder filled with air, with two circular faces of 10mm diameter and a length of 100mm. The electrodes are pressed ...
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1answer
31 views

Tesla Coil stops sparking until restart [closed]

I have a tesla coil with NT-1530-OUT Transformer, 23 turns (max) primary, 1m secondary(~1600turns), with MMC and rotary sparkgap. Gets 50cm sparks but try to tune the tesla coil by shifting top ...
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1answer
53 views

Why do charges move at the rim of the “charged-disk” conductor in response of the field created by themselves?

Okay, one statement from Purcell's book goes like: [...]Thus, we find the potential at $P_2$: $$\phi = \frac{1}{4\pi\epsilon_0} \int_{-\pi/2}^{\pi/2} 2\sigma\cos\theta d\theta = \frac{\sigma ...
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0answers
9 views

Net electric field of a nanowire in the vicinity of a quantumdot

I know how to find the electric field when both nanostructures are same and in the vicinity of each other. However, when it comes to nanostructures of different dimentionality (ie.nanowire and a ...
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1answer
40 views

Electric field at location of a charge due to the charge itself?

Suppose a charge $Q$ is put in the space at point $(x',y',z')$. What is the electric field value at point $(x',y',z')$?
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3answers
48 views

Drawing the lines of force for an electric field varying in magnitude but having a constant direction

How will the electric lines of force look for an electric field varying in magnitude but having a constant direction, say along +ve z axis ? According to me, since the electric field is varying in ...
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1answer
141 views

What is the meaning of $\vec{E}\times\vec{B}$?

Consider that for a single $\mathbb{R}^3$ point-source emitter of RF, the $\mathbf{E}$ and $\mathbf{B}$ fields (when treated as transverse sinusoids and ignoring interference properties) are always ...
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2answers
38 views

Why does the electric polarisation (polarisation density) have this direction?

It can be inferred that the amount polarisation $ P $ is dependent upon and proportional to the magnitude of the electric field $ E $ applied: \begin{equation} P \propto E. \end{equation} This ...
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2answers
56 views

Electric field in a non-uniformly charged sheet [closed]

So if we have a large sheet that is not uniformly charged and is NOT a conductor, how can I find an expression for the electric field everywhere? Things we know about the sheet: the width is 2b it ...
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2answers
48 views

When is work done on or by something?

An example, here what my textbook says: When charges are released In electric fields charges experience the force causing them to accelerate along electric field vectors. Positive charges ...
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1answer
48 views

Electric field between capacitors [closed]

A parallel-plate capacitor consists of two parallel, conducting plates of area $A$, separated by a distance $d$. Each carries a charge of magnitude $Q$; positive on one, negative on the other. ...
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0answers
15 views

Why the magnitude, $E$, of the field vector is different for every sets of (parallel) plates?

This is quoted my textbook. I wonder why we can't reproduce the same magnitude on a different set of plates, if we make them the same size, same charge, and having the same electric potential, and ...
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1answer
48 views

What do field lines between two like-charged parallel plates look like?

I couldn't find any image to answer my question on Google. But I guess it looks somewhat like this, correct?
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3answers
68 views

Which one of the two objects does the gravitation force vector point to?

My book tells me that the arrowhead should point to whichever is responsible for the field. Am correct in a assuming that it's whichever has the larger mass or bigger electric charge?
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1answer
18 views

Why can't objects made of insulating material “store excess charges”?

This is quoted from my textbook. I saw plastic objects before being able to store excess charges. For example, if you rub paper against a plastic pole. Both will gain charges. But in lab, I never ...
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1answer
59 views

Why isn't the electric field zero in the empty space?

A spherical portion has been removed from solid sphere having a charge distributed uniformly in its volume the electric field inside the emptied space is? Isn't the electric field suppose to be zero ...
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0answers
23 views

Imaging and the Electric Field

In this book (pg. 162), it mentioned that conventional lenses only focus propagating waves, thereby creating an imperfect image. In contrast, superlenses focus both propagating and evanescent waves, ...
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4answers
259 views

What is the *cause* of the Lorentz Force

Is it possible to explain what actually causes the force on a current carrying conductor in a magnetic field. I have read that this is due to the magnetic fields 'interacting' in some way. This ...
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1answer
31 views

How do I get the angle for the $x$ and $y$ component of the electric field for four equidistant particles?

Four particles form a square of edge length $a= 5.00\ cm$ and have charges $q_1= +10\ nC$, $q_2=-20\ nC$, $q_3=20\ nC$, and $q_4=-10\ nC$. In unit vector notation, what is the net electric field the ...
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1answer
42 views

How to calculate the potential energy of an $H_2$ molecule

From left to right, electron $e_1$, $e_2$ and proton $p_1$, $p_2$. $r_0=0.529nm$ The total energy is sum of energy require to bring each particle to its place. Take the place of $e_1$ is zero ...
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3answers
69 views

Is the electric field at a single point inside a charged sphere zero?

Many physics textbooks say, Gauss' law shows that the electric field inside a sphere with uniform charge distribution on the surface equals zero. What I want to know is, do they mean total, ...
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0answers
34 views

Finding Magnitude and Direction of Dipole's Electric Field at a Point

This question pertains to finding the magnitude and direction of a dipole's electric field. Specifically, I am trying to figure out why we are using both the hypotenuse and $\sin\theta$, and not the ...
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0answers
28 views

Where can I find a good theoretical treatment of conductor shielding?

Suppose one has three current carrying cylinders lying on the same plane. Some of the electric field of the first conductor ends up on the second conductor, which creates capacitance C12. But also ...
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1answer
177 views

Electric field due to an electric dipole at a point on the equatorial line

According to [tamilnadu][1] textbook Electric field due to an electric dipole at a point on the equatorial line is given as The direction of E is along ...
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1answer
64 views

Fringing effect of electric current

We know the what is the fringing effect of electric field in capacitor, of magnetic field in some in some solenoid or magnetic field in through joint of some metal. But is there is something similar ...
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0answers
57 views

$E$-field from changing current in straight wire

A very long insulated wire oriented along the $z$ axis of a cylindrical coordinate system is carrying current that is defined by the following function: $$I(t) =Io + k⋅t$$ (current increases linearly ...
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1answer
80 views

Can electric field lines “sometimes” pass through conductors' surfaces?

I have a rather general question about electric field lines. If we have a hollow and neutral spherical shell and we place somewhere inside it a charge QA=+q, the electric field outside of the ...
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1answer
57 views

Why is this electric field due to one plate of a capacitor $\sigma / 2 \epsilon_0$ when the capacitor plates are finite?

We know that electric field due to an INFINTE large sheet is constant and at INFINTY the electric field is not zero. But say if I take a finite sheet of length l and width w. Then the electric field ...
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0answers
17 views

How does one start drawing electric fields? [duplicate]

How does one start drawing electric fields.you are given two charge.now there are infinite electric field lines so how do you show greater electric field by drawing denser lines.After all there can be ...
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2answers
104 views

Why is the Electric Field Zero at this point?

In a Phet Lab simulation, which is all I have at the moment to do my learning on electric field forces, the point represented as colored on the diagram below is shown to have an electric field ...
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0answers
27 views

Sign of an electric field in electric potential energy problem

I was wondering why the electric field E in this problem is negative. Is it because the earth is negative? We can assume that near the Earth’s surface, a uniform electric field is set up thanks to ...
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1answer
30 views

What is the purpose of defining an electric field, and how to apply it?

So, I've been reading an introductory book to physics. I've gotten to the point where I understand Coulomb's law, and now the book is introducing electric fields. I'm having a hard time ...
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68 views

What is the cause of the time-varying electric and magnetic near-fields around a wire with a 60Hz AC current?

I know that it's the accelerating electrons in an AC current that are the cause of far field effects. But, what about the reactive near field close to a wire that has a 60Hz AC current? What is the ...
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1answer
76 views

Is my understanding of electric fields accurate?

Could someone please help me and let me know if the statements below are any accurate? I am struggling trying to understand what electric fields are and I could really use some help! An electric ...
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3answers
101 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?
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1answer
182 views

How to approximate trajectories and movement of two oppositely charged particles?

Imagine a single, stationary charged atomic ion, say a Lithium anion or cation (Li+ or Li-). Now imagine another a single free, oppositely charged particle--perhaps an electron or Hydrogen ion ...
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2answers
73 views

Why is the electric field highest in regions of highest resistance?

I know Kirchhoff's law and that current must be constant. But what exactly is the phenomenon, from first principles, that causes the electric field to be stronger in a region with lower carrier ...
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1answer
28 views

Change in Potential energy moving toward line of charge

I'm analyzing the energy involved with charges moving in an electric field and I'm getting caught up here and I must be missing something. So given that an infinitely long line of charge produces a ...
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1answer
31 views

Electric Flux through metal plate by uniformly charged wire

Suppose a long uniformly charged wire is placed parallel to a thin uniform metal plate of length l and width $w$. Distance is $r$. Then how to calculate the electric flux through the plate if the ...
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0answers
11 views

Flux due to a charge placed just outside the vertex of a cube [duplicate]

There was a solved example in my book on Gauss's Law. The question says that there is a charge q placed at a distance d outside one of the vertices of a cube such that d tends to 0.My objective is to ...