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Questions tagged [charge]

A fundamental property of matter which causes it to experience electromagnetic forces.

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Electric field experienced by a charge

We have two charges, say $Q_1$ and $Q_2$. The magnitude of the electric field $E$ experienced by charge $Q_2$ is: $$E = \frac{k Q_1}{r^2}$$ where $k$ is Coulomb's constant and $r$ is the distance ...
user134613's user avatar
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Electric field at a point due to dielectric inserted in between a parallel plate capacitor [closed]

Here, I have a parallel plate capacitor with each plate having surface charge density $\sigma$. A dielectric of dielectric constant $K$, is inserted partially between the two plates. What would be the ...
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What is the associated charge for the weak neutral current?

So for the strong force, there's color charge; for electromagnetism, there's electric charge; and for weak charged current, there's weak isospin. How about the weak neutral current? Is there an ...
Positron99's user avatar
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What is the charge distribution on a parallel plate capacitor when one plate is grounded? [closed]

Let's say a large parallel plate capacitor is connected to a DC power supply. Then, the charge on the two plates will be +CV and -CV. If I ground the negative terminal (both the capacitor's and the ...
Михаил Чиланнов.'s user avatar
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Flux change through a loop

I'm having difficulties understanding this thing. It would be lovable if someone could show me its derivations and prove it: In a conducting loop, there is a relationship between the total displaced ...
AhmedSahraoui's user avatar
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Electrostatic potential outside of a charged ball [closed]

To preface, I have never solved Maxwell's equation or his resulting Poisson's equation in any coordinate scheme, nor am I a physics major. I'm entirely teaching myself how to do this, so I don't know ...
Researcher R's user avatar
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Is there any specific terminology for this type of current in spintronics?

In spintronics, there are several types of currents: Spin-polarized current: The two spins flow in the same direction with unequal contributions. Perfectly spin-polarized current: Only one species of ...
Isaac Wang's user avatar
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Does the geometric shape of the cross-section of an infinitesimally thin conducting charged thread (wire) affect its electric field?

Assume that a solid conducting torus (toroidal ring), with a cross-section of a circle of (minor) radius $r$, is negatively charged. Solving Poisson's equation, we can find the charge distribution of ...
Mohammad Javanshiry's user avatar
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How does this proof of Gauss’ law generalize from $1$ to $n$ charges?

I am having trouble seeing how the proof of Gauss’ law for one charge generalizes to hold for multiple charges in Griffiths’ introduction to electrodynamics. Gauss’ law is proved for one charge (for ...
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Voltage: work to move a charge, or difference of electric potential?

Let's say I have a single positive charge inside of an electrostatic field. I want to move this charge from point A to point B and determine the voltage between the two points. Points A and B are the ...
oh no's user avatar
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Charge besides conductor

This is a curiosity What would be net charge induced on a (say spherical) conductor when a positive charge is placed besides it. What I think is that a negative charge will be induced on surface near ...
Mainframe's user avatar
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What is charge on a fundamental level and what is it caused by?

On bigger bodies, I've learnt so far that charge is caused by a lack or excess of electrons or protons but when you look at an electron or proton, how are they charged? what is the cause of their ...
shriekspeare's user avatar
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Understand power rating in layman terms

I have recently started the chapter of electricity of class 8. I am not understanding the concept of power rating of appliances. When we say that a bulb is rated 220V-100W, which means, according to ...
Sanchit Batra's user avatar
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Volume distribution of charge in a wire in a DC circuit

According to this and several other articles some amount of charge in a DC circuit distributes itself on the surface of the conductor, making the electric field inside parallel to the said surface. ...
user567_9's user avatar
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Why don't positively charged metal ions (in a wire) move but electrons do?

I'm very confused on this question. I've researched online but I can't seem to find the answer anywhere: all I was told was that electrons move (as part of electron flow) towards the regions of high ...
Nadia Nowak's user avatar
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Charge conservation in ohmic material - Apparent paradox

Consider an ohmic material with constant conductivity, which obeys the relation: $$\vec J = \sigma \vec E$$ where $\vec J$ is the current density and $\sigma$ is the conductivity. Applying the first ...
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Self-Energy of a Conducting Shell based on Surface Charge Distribution

If a charge $q$ is given to a shell of radius $r$ (conducting or non-conducting) it's self-energy is $kq^2/2r$, $k$ being Coulomb's constant. But if the shell is conducting and the charge on the inner ...
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Is charge an intrinsic property of matter? [duplicate]

Is charge an intrinsic property of all the particles that comprise matter or is it an intrinsic property limited to certain fundamental particles only?? Or the question can be revised as "Does ...
Kunal Prajapat's user avatar
1 vote
2 answers
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Why is the electric potential from a positive sphere not negative? [duplicate]

Say we have a positive point charge located somewhere. Then the electric field due to this point charge is $\vec{E} = \frac{1}{4\pi \epsilon_0}\frac{Q}{r^2}\hat{r} $ , now considering potential is $V =...
J. Doe's user avatar
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Densities at a Point

I was recently reading Purcell’s text on electrodynamics. He generalizes Coulomb’s Law by introducing charge densities. However, what does the density at a point represent? (Since Purcell took charge ...
V T Naveen Mugundh's user avatar
2 votes
2 answers
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Dipoles as vectors

A triatomic molecule $X_2Y$ has plane structure as shown in figure. Due to difference in electronegativity, charge acquired by each X atom is $q$ and charge on Y atom is $- 2q$. The bond length ...
Anshu Gupta's user avatar
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Double-slit experiment with accelerating charged particles

As I understand, charged particles that are accelerated will emit photons. I assume that it is possible to set up a double-slit experiment where the particles, say electrons, are accelerated from when ...
DSE's user avatar
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Does cutting out the surfaces with no surface charge affect the charge distribution on the remaining parts of a conducting surface of arbitrary shape?

Assume that we have an arbitrary conducting surface being charged positively/negatively. Also, assume that we have extracted charge distribution by solving the Poisson's equation with proper boundary ...
Mohammad Javanshiry's user avatar
1 vote
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Total charge within a sphere

Consider an electric field in free space with $$ \mathbf {D} = -3z\mathbf {a_r} μCb/m^2 $$ I need to calculate the total charge within a 3mm sphere centered at (0,1,1). I calculate the charge ...
Pavlos Papanikolaou's user avatar
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Surface charge density within a parallel plate capacitor on different voltages

I need a way to vary the surface charge density without changing the electric field. My idea is to use two large conducting parallel plates close to each other in vacuum enclosed in a grounded vessel (...
Sibo's user avatar
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1 vote
2 answers
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Divergence of Electric Field of Point Charge is always zero [closed]

I might have a bug in my brain, but I just can't figure this out. Please help. According to the first of the Maxwell Equations, we have $$ \nabla\cdot\vec{E}=\frac{\rho}{\epsilon_0}. $$ And we have ...
tobi-v's user avatar
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How many photons pass through us every second?

I just read this answer https://physics.stackexchange.com/a/229374, which says that, when a magnet rotates, photons are emitted with wavelength $λ=c/f$, where $f$ is the frequency of rotation. And ...
Flamethrower's user avatar
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Question about electric field around charge density

Suppose the region $0 < x < d$ has charge density $-p$, and the region $-d < x < 0$ has charge density $p$. Why is electric field on the edge of region in point d zero? If negatively ...
Kopun Vukašin's user avatar
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Is charge an intrinsic property of "all" the fundamental particles or an intrinsic property of "certain" fundamental particles?

Charge is said to be an intrinsic property of particles of which matter is made of. First of all, what does the word "Intrinsic" actually signify in this context?? Does it mean that "...
Kunal Prajapat's user avatar
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Both charge and mass are intrinsic properties of matter. So for the existence of matter, should both mass and charge exist simultaneously? [duplicate]

Recently, I came across a book which stated that "Mass can exist without charge but Charge cannot exist without mass". Is this statement really correct? As if we look intrinsically in a ...
Kunal Prajapat's user avatar
5 votes
3 answers
412 views

Why is the universe charge-neutral?

The positive charges (such as from the protons) of the universe are almost neutralized by the negative charges (such as from the electrons). Is there an explanation for this neutrality? Does it ...
MadMax's user avatar
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Is it valid to write $\int{dq}$?

While I was going through the expression for the electric field in continuous charge distributions (Section 2.1.4) in Griffiths' textbook, it was given as $${E(r)} = \frac{1}{4\pi\epsilon_o}\int{\...
Sahil Muhammed's user avatar
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Does an oscillating electron whose axis of oscillation is rotating behave as a magnetic dipole?

An electron is located at the origin in the x-y plane. To begin with, it oscillates along the y-axis. With time, the axis of oscillation rotates around the origin in the x-y plane at an angular speed $...
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Uniqueness of charge distribution in conductor

I found out about a result describing the uniqueness of the charge distribution on a conductor. It says that for a given total charge on a conductor and a given charge distribution of the outside (...
FundamentalTheorem's user avatar
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How do charges on two conductors charged by the same battery relate to each other?

Let’s consider 2 neutral conducting spheres, L and R, with different radii. There is a battery somewhere in the middle between these spheres. The battery has potential $\phi_{B-}$ on its negative ...
Alexandr's user avatar
6 votes
1 answer
189 views

Accumulated charge in conductors

Conductors placed in electric fields undergo a redistribution of charges. There is a separation of charges which occurs only on the surface. But what prevents the charge from leaving the surface of ...
Users's user avatar
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1 answer
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Gauss's Law vs Image charges

Consider a grounded shell of radius $R$, inside is a point charge $q$ at a distance $a$ from the centre. Now, this charge would induce an amount of charge $-q$ on the conductor, whose field would be ...
Vivek Kalita's user avatar
1 vote
1 answer
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Potential on conducting shell without image charge

Edit 2: I know how image charges work. But I'm still trying to rationalize without it. Edit 1: scrap this, realized what I needed was image charges. This entire question is sort of a jury-rig ...
zxayn's user avatar
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A General Analysis of Charge Distribution inside conductors

I'll go ahead and present my question straight-forward and then talk about the calculation details.My Question is: how do you define a conductor in Electrostatics? What are the basic(minimum) set of ...
Charu _Bamble's user avatar
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Dirac's quantisation condition and non-quantised charge

After some time searching for a convincing demonstration of the Dirac quantisation condition, I've finally come across not one but three of them in David Tong's book: Gauge Theory. Nonetheless, it all ...
Lagrangiano's user avatar
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Why does charge reside on the outer surface for a conductor but inside in case of an insulator? [duplicate]

So from what I understood, in case of a conductor there are free electrons and when its charged there is maximum repulsion between the like charges which causes the electrons to reside on the surface ...
Suja Harshitha's user avatar
2 votes
0 answers
114 views

What are the limitations of Nodal Analysis?

Yea, that's the question basically. What are the limitations of Nodal Analysis? Like, for example take the following case, we have to find out the net capacitance between A and B. Now I want to solve ...
Adhway's user avatar
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Induced charges due to uniform electric field

Suppose there is a finite metallic conductor placed in a uniform electric field. Will the magnitude of positive or negative charge induced on it depend on its shape or will it only depend on the ...
Gautam's user avatar
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Total charge on a polarized neutral dielectric

I'm going through Griffith's EM book right now and from problem 4.14 we can see that the total charge on a polarized neutral dielectric is 0 (since it is neutral) the polarization may move around some ...
mastershooter77's user avatar
2 votes
3 answers
197 views

Is Coulomb's law wrong?

Recently I was reading about Coulomb's law which states that: "Magnitude of the electrostatic force F between two point charges $q_1$ and $q_2$ is directly proportional to the product of the ...
Ishaan's user avatar
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Equipotential surface of Hemispherical charge distribution

I was attempting a question of electrostatics from the book Pathfinder for Olympiads and Jee advanced Physics. In a solution of certain question, the base of a uniform hemispherical charge ...
Navanieeth TS's user avatar
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What would happen to a system of two identical charges one with velocity $v$ and other at rest given unlimited time?

Two identical charged particles one having velocity $v$ and other starts from rest along a straight line. What would happen given an unlimited time? I think the charge initially at rest should keep on ...
Anvi Mahajan's user avatar
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1 answer
63 views

Does QED explain why Moving charge produce magnetic field? [closed]

I wonder that moving charge produce magnetic fields. Now a days quantum field theory explain much of particle physics their underlying mediate particles. But can QED explain why moving charge produce ...
Sanket Thakkar's user avatar
3 votes
2 answers
129 views

Radiation from accelerated charged in a co-accelerated reference frame

I was wondering if I sit on a accelerated charge particle I will not observe radiation since the particle is at rest according to me. But my friend observes it from outside and he will see radiation ...
physics's user avatar
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0 answers
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Can two positive electric conductors attract each other in some cases?

Can two positive conductors attract each other in some cases? In my opinion, let me denote the two conductors by $Q_1,Q_2>0$. Suppose $Q_1>>Q_2$ and $Q_2$ is really small. Let a tip of $Q_1$ ...
Luosw's user avatar
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