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0
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0answers
19 views

Calculation of the electric field from a cube of charge with charge density proportional to radial distance [on hold]

I have a cube of side length $L$ centered at the origin and total charge $Q$; the charge density is $\rho(r)\propto r^n$ for some integer $n$, where $r$ is the radial distance in spherical ...
3
votes
0answers
45 views

Electric field in a sphere with a cylindrical hole drilled through it

Suppose that you have a sphere of radius $R$ and uniform charge density $\rho$; a cylindrical hole with radius $a$ ($a\ll R$) is drilled through the center of the sphere, leaving it like a "necklace ...
3
votes
1answer
54 views

Does it really make sense to talk about field lines?

Field lines should only provide a visual representation of a field. There is a rule for their construction: take an object subject to a field, move it by d$\mathbf{r}$ and draw the direction of the ...
0
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0answers
20 views

What's the proof that the polarization occur s to the electric field of the light? [duplicate]

What's the proof of the light polarization that it happens to the electric field and not the magnetic field? How did Malus discover that the light is polarized although he didn't see the waves ...
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2answers
65 views

Why doesn't the magnetic field polarize when polarizing light?

If the magnetic field doesn't polarize does it follow the electric field path of propagation? or does it vanish?
0
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0answers
27 views

Is this expression of electric field correct?

I know that the electric field component of electromagnetic wave should be written as the first equation shown, but some times it can be expressed in terms of complex amplitude of electric field as in ...
1
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2answers
51 views

Interaction energy between dipole and potential

It is known that interaction energy = $-\vec{p}.\vec{E}$ where $\vec{p}$ is dipole moment and $\vec{E}$ is the electric field. I have to calculate the interaction energy of a system whose dipole ...
1
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2answers
109 views

How electromagnetic fields travel through vacuum?

How electromagnetic fields travel through vacuum is it right to say that they propagate or travel? do they alternately form each other by charged particles?
1
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1answer
83 views

What is the outcome of a changing Magnetic Field?

The question might sound elementary. However, the thing is this. Changing Magnetic field produces a changing electric field. That changing electric field would produce a changing magnetic field. So, ...
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5answers
1k views

Why can two (or more) electric field lines never cross?

The the title is self explanatory, I guess. Why can two (or more) electric field lines never cross?
0
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0answers
15 views

Electric field for two adjacent infinite layers of width h charged + and − uniformly

I'm trying to figure how to calculate the electric field created by two adjacent infinite layers of width h charged + and − uniformly. I don't understand why isn't the field outside of the layers ...
2
votes
2answers
67 views

Does field line concept explain electric field due to dipole?

Consider an electric dipole consisting of charges $-q$ and $+q$, separated by a distance $2a$ and placed in free space. Let $P$ be point on the line joining the two charges (axial line) at a distance ...
7
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6answers
566 views

Why cant Electrostatic field lines form closed loops?

My physics textbook says "Electrostatic field lines do not form closed loops. This is a consequence of the conservative nature of electric field." But I cant quite understand. Can anyone elaborate? ...
1
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0answers
26 views

charged oil drop in electric field [closed]

I am currently doing coursework for my A2 physics course. I am dropping a charged oil drop in a horizontal electric field and I was wondering how to calculate how much the droplet would deviate given ...
4
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1answer
76 views

Poynting theorem and entering power

I refer to the time-domain version of the Poyinting theorem in electro-magnetism: $- \displaystyle \oint_S (\mathbf{E} \times \mathbf{H}) \cdot d\mathbf{S} - \int_V \mathbf{E} \cdot \mathbf{J}_i \ dV ...
1
vote
1answer
55 views

Field from non-conducting plate?

For a non-conducting sheet, the electric field is given by: $$E = \frac{\sigma}{2\epsilon_0}$$ where $\sigma$ is the surface charge density. This equation holds well for a finite ...
1
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1answer
56 views

Electric field near surface of a conductor? [duplicate]

If the electric field on a positive charge is non-zero, then the charge accelerates in the direction of the field. The field at the surface of a conductor is perpendicular to the surface. Why ...
0
votes
1answer
101 views

Calculating the electric potential in cylindrical coordinates from constant E-field

I am having so much trouble with this problem. I feel like I shouldn't be, but I am. A uniform electric field, $\vec{E} = E_0\hat{x}$. What is the potential, expressed using cylindrical ...
2
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3answers
79 views

Calculating the Potential from the E-Field

I find that often times I'll be tripped up by questioning whether or not I can do something mathematically, and be unable to come up with a satisfying answer. This is, unfortunately, one of those ...
2
votes
1answer
68 views

What does the electric field caused by a charged cylinder look like?

I am talking about a cylinder with a large enough radius:length ration that it cannot just be treated as a line. I would think that the electric field lines come out the curved and flat surfaces ...
1
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1answer
107 views

How can electrons move along the conductive wire? ( seems to be a paradox )

Tangential components of the electric field across an interface between two media, with no impressed magnetic current densities along the boundary of the interface, are continuous. So: $ n \times (E_2 ...
6
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2answers
119 views

Quantization of electrostatic $\vec E$ field?

Can a electrostatic field $\vec E=\vec E(x,y,z)$ (time-independent) or electrostatic potential $\phi=\phi(x,y,z)$ be quantized? If yes, will these quanta be photons again? But we don't have an ...
2
votes
0answers
31 views

Electric field of a capacitor in dielectric medium with weird size

I have been learning gauss's law in capacitor recently, recently I come up with this problem that I couldn't solve myself. If we have a capacitor,and a dielectric medium with half the volume between ...
1
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0answers
65 views

Electric field produced by a charged ring

I have a question I couldn't find an answer for anywhere. There is a ring of radius $R$ which is charged uniformly with linear density $\lambda$, and I have to find the electric field on any point of ...
0
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2answers
67 views

What is meant by “net charge”?

Lets consider a system of two opposite charges separated by a certain distance (dipole), if we ask what is the net charge for this system? the answer would be zero. The net charge (what I have come ...
-1
votes
1answer
48 views

Electric Potential Energy

When work is done on a positive test charge by an external force to move it from one location to another, does the potential energy increases or decreases, and does the electric potential increases or ...
3
votes
1answer
74 views

Are the axial electric field lines of a dipole the only ones that extend to infinity?

Consider an electric dipole and its electric field lines. There will be many field lines that do not extend to or originate from infinity, but rather begin at the positive charge and loop back ...
0
votes
2answers
87 views

Conversion of Moving coil galvanometer to ammeter

A galvanometer can be converted into an ammeter by connecting a low resistance (called shunt resistance) in parallel to the galvanometer. Firstly, why do we need to connect the resistance? If a ...
0
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0answers
30 views

Force exerted by a capacitor on a polar object

I was reading about capacitors and wondered what the force an electrostatic field created by a capacitor would be on an object with a certain charge and mass. If it can exert a force on a polar object ...
1
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3answers
124 views

Conservation of energy in electromagnetism?

How is energy conserved in electromagnetism? Is it hinted only from Lenz's law or from Maxwell? Also, if a solenoid's flow of current produces a magnetic field, and from the magnetic field forces are ...
5
votes
4answers
358 views

How electron movement produces current,instead of having a slow drift speed

Just need a clarification here, how the current is produced due to the movement of electrons, in an external circuit,having a very slow drift speed. Normally in a battery there is high potential ...
2
votes
1answer
229 views

Finding electric field between overlapping surfaces [closed]

The problem is: A sphere with radius R is centered at the origin, an infinite cylinder with radius R has its axis along the z axis, and an infinite slab with thickness 2R lies between the planes ...
1
vote
0answers
66 views

Electric potential on a uniformly charged tube

A hollow cylinder, with no top or bottom, of radius $R$ and length $L$ is uniformly charged with density $\sigma>0$. I have to find the point on space where a point charge $q>0$ has to be drawn ...
0
votes
2answers
63 views

Why is there no way to make electric field at point P zero by changing quantity and sign of charge of $q_1$? [closed]

q1 = -2.4μC and q2 = 8.9 μC, q3 = 2.3 μC, d is 6.2cm. Suppose that we want to make electric field at point P zero. We leave everything about q2 and q3 as they were before, but we are allowed to ...
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0answers
76 views
0
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0answers
124 views

Apply Gauss' Law to find Electric Field around nonconducting plastic sheets

The question: Two very large, nonconducting plastic sheets, each 10.0 cm thick, carry uniform charge densities $\sigma_1$,$\sigma_2$,$\sigma_3$ and $\sigma_4$ on their surfaces, as shown in the ...
0
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1answer
1k views

A point between two charges has an electric potential of zero, but a charge placed at this point will gain kinetic energy. Why?

If I have a positive charge of +q and a negative charge of -q that are set a distance of r apart from each other, their midpoint will have an electric potential of zero. However, if I put a test ...
8
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2answers
2k views

What is the difference between an electric and a magnetic field? [closed]

This question is a consequence of another question of mine which is about spin. Here is my spin question. What is the difference between these two fields? How do they occur? Am I right if I say that ...
0
votes
1answer
49 views

Electric field from a sheet of charge?

Does anyone have images of the electric field created by a real plate of charge? I'm not looking for an image of a theoretical infinite sheet of charge, I'm looking for an image of a real large one. ...
2
votes
5answers
112 views

Why is electric potential 0 in this case?

On a test, we had a question where there are 4 point charges at the vertices of a square. The 2 charges at the upper vertices have charges of +q and the 2 charges ...
0
votes
4answers
263 views

Does a charge experience no force due to electric field produced by it?

My book "Concepts of Physics (Satish K. Gupta)" says: The electric field of a charge is the space property by virtue of which the charge modifies the space around itself. As a result, if any ...
1
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1answer
273 views

How to choose Gaussian surfaces while solving problems?

I have a doubt regarding this problem: Two large identical flat metal plates are placed parallel to one another, seperated by a small distance compared to their linear size. One plate is given a ...
3
votes
1answer
198 views

What force particle mediates electric fields and magnetic fields?

The force carrier for magnetic fields and electric fields are supposedly photons. I don't get it: 1) Wouldn't that mean that a charged particle (e.g. an electron or even a polarized H2O molecule) ...
0
votes
1answer
317 views

Does displacement current exist after the capacitor gets fully charged?

The displacement current is due to changing electric field. Since, after the capacitor gets fully charged there is no changing electric field there is no displacement current.(capacitor connected to a ...
1
vote
1answer
99 views

What happens to a conducting ring when exposed to an electric field?

It might be a silly question, but one of my friends just got asked this question at an oral exam, and he could not answer it, and didn't receive the answer either (Or at least he forgot). And I've ...
1
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0answers
77 views

Complex polarizability of a dielectric sphere in a homohenious electric field

It is well known that complex polarizability of uniform dielectric sphere with radius $r$ and complex permittivity $\hat\epsilon_{in}(\omega)$ placed in a medium with complex permittivity ...
2
votes
1answer
44 views

Separating the convective and the inductive electric field

My question is basically this, if I am only able to measure the total electric field and the magnetic field at a few discrete points in space and time, is it possible to separate the convective and ...
0
votes
1answer
78 views

Show that the electric field, $\mathbf{\vec{E}}$ cannot be generated by any static distribution of charges

Show that the electric field $$\mathbf{\vec{E}}=\begin{pmatrix}0 \\ E_0x \\ 0\end{pmatrix}$$ where $E_0$ is a constant, cannot be generated by any static distribution of charges. I understand ...
5
votes
2answers
135 views

Could we run an electric car on electric eels?

Could we run an electric car on a tank full of electric eels? I've heard electric eels are around 400 to 500 volts and can keep shocking for up to an hour. They also have a 10 volt system to sense ...
2
votes
1answer
69 views

Why is photon annihilation associated with the POSITIVE frequency component of the electric field?

I'm reading Glauber's paper "The quantum theory of optical coherence". In his work he does not introduce the annihilation and creation operators, but he refers instead to the positive and negative ...