Questions tagged [charge]

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

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What electric field will be generated by a magnet rotating around a center with radius $R $? What will be electric field at center?

Lets say there is a charged particle at the center and magnet is rotating around it with radius R facing its north pole towards the charge. What will be electric field at the charge and what force the ...
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Do vacuum virtual patricles have mass? [duplicate]

When a particle and antiparticle pair is produced their charge sum is zero,momentum sum is zero but the mass sum isn't.Does that mean that possibly for the mass there is no need of starting ...
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Electric charge on a capacitor [closed]

What is the electric charge on the capacitor with 3μF? I've tried to apply Kirchhoff voltage law on each mesh, but isn't there any short procedure for it? Many thanks in advance.
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What is surface bound charge? [closed]

what is surface bound charge ? how to calculate it?
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What is the maximum charge a conductor can hold? [closed]

My question goes: what is the maximum charge a conductor ball with 15cm radius sitting in air can hold?
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Why is energy absorbed by the battery when the plates of a parallel plate capacitor are pulled apart?

It is said that when the plates of a parallel plate capacitor connected to a battery are pulled apart to increase the separation, energy is absorbed by the battery and no heat is produced during this ...
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Does electric charge vary between observers?

I understand that certain observations such a length and mass vary depending on observers in different frames of motion and gravity. I was wondering if the electric charge changes in a similar way. ...
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What does the interaction between two charges depend on?

In our intro to electrodynamics course, we were told that the interaction between two charges depends on: ➢Magnitude of the charges ➢Separation distance between the charges ➢Velocities of the ...
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How can I prove that the Noether charge represents actually conservation of electric charge?

I have a question about Noether's theorem for global gauge invariance of a complex scalar field. Starting from \begin{equation} \mathscr{L} = \partial_{\mu}\Phi \partial^{\mu}\Phi^{*} + \frac{m^2c^2}{...
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Sphere, dielectrics and bound charge

I have this situation. A conducting metal sphere of radius $a$ and charge $Q$, surrounded by a dieletric shell with inner radius $a$ and outern radius $b$. If I try to evaluate the induced charge ...
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What do we mean by charge in physics?

I am drawing the comparison between electrical charge and colour charge, in electric charges they communicate with (virtual) photon and photon itself is a boson carrying no charge. How about colour ...
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Finding the direction angle of an electrostatic force [closed]

I am given two points: q1=5.8×10-9 C at (0.0022 m, 0), and q3=4.1×10-9 C at (0,0). I have already found the force on q3 by q1 to be .044 N, but now I need to find the direction angle of the force on ...
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Can particle with fractional charge exist in isolation?

Since quarks are ruled out I wonder if it is possible for free fractional charge to exist not counting virtual particles?
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What is the relationship between charge and mass of electrons and protons? [closed]

Proton and electron have equal and opposite charge but they have a different mass how is this possible
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How to know charge of a particle from position and momentum?

It was mentioned in one documentary that the only think we need to know about a particle is it's position and momentum, so we can calculate every other quantity from this. If it is correct how do we ...
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Representation of $\mathfrak{u}(1)$ on quantum fields associated to charge

This question is a followup to this question of mine and is about making sense of a mathematical construct. Suppose one has a multiparticle Fock space with several species of particles labelled by $n\...
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Why is ampere still a base unit? [duplicate]

The ampere is still a base unit, according to the SI brochure. However, in my perception the recent redefinition of units effectively defines the Coulomb as e/(1.602 176 634 × 10^−19), and the ampere ...
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Weinberg's argument for antiparticles: is this really a necessary condition?

In Chapter 5 to "The Quantum Theory of Fields" by Weinberg he gives a nice point of view on antiparticles. He says the following (I've called the last equation (*) because it is not numbered in ...
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What is the analog between charges and mass with regards to vector fields? [duplicate]

A way to think about gravitational fields is that they spawn as a consequence of mass literally bending time and space. Is there an analog of this concerning charges and the electric field intensity?
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Potential energy in a field and potential energy between two objects? (Electrostatics and Gravitation)

What is the difference between the electrostatic potential energy of a charge immersed in an electrostatic field and the potential energy between two charges? Is there a connection between the two?...
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Virtual electron contribution to electron charge

Renormalization, or "a dippy way to to sweep all this stuff under the rug", makes QED the most accurate science ever. I came across a value that explained the difference between the predicted electron ...
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Electron volt to volt question

An $\rm{eV}$ (electron volt) is equal to a volt. So that volt it is equal to, is it based on 1 volt rms or one volt peak to peak or one volt average, or some other calculation of a volt?
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Effects of the electrostatic field

If we have a [positively] charged sphere like this: do the charges on the one side stop the effects of the electric field of the charges on the other sides of the surface? In other words, is ...
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Virtual electron charge

Since the total charge of an actual electron has been shown to have a contribution from virtual electrons, what is the value of the virtual electron charge contribution?
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How charges behave with one another in ball lightning?

I was reading about lightning and in due process I found about something called ball lightning. While talking about the possible causes of ball lightning this article refers to a paper which proposes ...
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Is electric current just the rate of flow of charges? [duplicate]

I was going through the differences between Conduction and Displacement current. Conduction current is just the flow of electric charges but when we come to Displacement current, we see that there is ...
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Charge inside a charged hollow conducting sphere with a hole

How are the following results theoretically explained? As part of an electrostatics exercise we were to measure the charge on the outside and inside surfaces of a charged hollow conducting sphere ...
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Does the work done in moving a charge through a conductor depend on its length?

Potential difference between two points is defined as the work done in moving a net positive charge from one point to the other. But, my question is, when the two points, that are potentially ...
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Supposed charge distribution on a metallic sphere

Usually when we talk about charge distribution on a sphere we say that excess charge resides on the surface of metallic sphere. As is said here: The net electric charge of a conductor resides ...
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Few conceptual doubts based on the effective capacitance of two metallic spheres joined by a metallic wire

The following problem is from Concepts of Physics by Dr. H.C.Verma, from the chapter "Capacitors", page 166, question 12: Problem: Two conducting spheres of radii $R_1$ and $R_2$ are kept widely ...
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Why is the electric field of Gauss law applicable for charges both in and around?

We know that the L.H.S of Gauss law $E.dS$ is applicable for all charges in and around but R.H.S $Q$ is only for charges enclosed. Now my question: Lets say you have two gaussian surfaces of same ...
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Where does the potential energy come from for a charge?

The potential energy of a charge which is brought near another charge (of the same sign) from infinity by applying an external force which is equal to the electrostatic force of repulsion. The ...
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If two charges follow identical, curved paths, at equal velocities, and are equidistant at all times, will they exert magnetic force on each other?

Imagine one charge rotating in a circular orbit about a point, and another charge rotating about another point slightly below the first, tracing out two parallel circles on the outside of a cylinder. ...
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Why is capacitance inversely proportional to voltage? And not just the electric field [closed]

I understand that the capacitance should be inversely proportional to the electric field, since if the electric field is greater, the charges can leak out towards the other plate. But why should it ...
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Tabletop experiment that demonstrates the “electric charge comes in discrete unit”

James Gleick writes in his Feynman biography (Genius) that The difficulty concerned the electron, the fundamental speck of negative charge. AS a modern concept, the electron was still young, ...
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Conductor with cavity: net charge?

Suppose that we have a uncharged spherical conductor that carries a cavity with a charge $+q$ in it. The problem I am dealing with consists in answering this question: What is the field outside the ...
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Electron flow and electric field question [duplicate]

My understanding is that the electric field lines of a proton goes outwards and an electron goes inwards, are theses properties the same for electron flow or is just for conventional current? I think ...
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How are charges redistributed on a system of parallel conducting plates? [closed]

I’ve seen quite a few questions where some charge is given to a conducting plate and we are to find the final charge on each face of the plate and on the faces of some nearby plates. While there have ...
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Potential energy required to setup a charged shell of charge Q

As shown in my textbook we find work done to bring dq charge from infinity and integrate it to get total work.But if we cannot bring whole Q charge at once then place on that metallic shell then ...
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Electric Flux associated with objects in Uniform Electric Field

If you have a cube in a uniform electric field , the net flux associated with it would be zero (because the no. of lines entering = no. of lines leaving). Suppose now you put a sphere in a uniform ...
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Work done by battery on a capacitor

Work done by battery on a capacitor is QV/2, where V is the final potential across the capacitor plates an Q is the charge. I know that the Q charge which gets stored on the capacitor comes from the ...
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How is the “charge on a capacitor” defined when two plates are unequally charged?

In Concepts of Physics by Dr.. H.C.Verma, in the chapter on "Capacitors", in page 144, under the topic "Capacitor and Capacitance" the following statement is given: A combination of two conductors ...
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Find the total charge of the sphere when density is given [closed]

You have a sphere with a charge density of $\rho=Ar^4$, where $A$ is some constant and the sphere has a radius $R$. What is the total charge of the sphere? I know that: $$Q=\int\int\int \rho \ \...
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Quantum field theory, interpretation of commutation relation

Let $\phi$ be the quantum field $$ \phi(x) = \int \frac{d^3\mathbf{p}}{(2\pi)^3} \frac{1}{\sqrt{2E_\mathbf{p}}} \Big[ b_\mathbf{p}e^{-ip\cdot x} + c_\mathbf{p}^\dagger e^{ip\cdot x} \Big] $$ with ...
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Is the net charge on a capacitor zero? If yes, then why?

I know that a capacitor has positive and negative charge distribution on either of its plates. But saying that net charged provided to it by the connected battery is zero doesn't seem to be correct. I ...
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Why does the potential energy of the system decrease when two charge balls are connected using a connecting wire

I am confused because I've seen in textbooks and online solutions to questions that when connected,the potential energy of a system of two charged spheres decreases.But according to law of ...
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The net charge of Earth

Shouldn't the earth have an over all small positive net charge? Cosmic rays in the form of light or high energy particles can ionize atoms, when that happens the electron and the positive ion recoils ...
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Given Electric Field Find Charge Distribution [closed]

The electric field is $\vec{E}=2xy \hat{x}+x^2\hat{y}$. Find the charge distribution that generated this field. My solution is based on differential form of Gauss's Law: $$\vec{\nabla} \cdot \vec{E}...
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Could electromagnetic forces theoretically move any type of particle?

I know electromagnetic forces (not specific on the source) can affect matter particles of various types, but can they exert effective force on any type of matter particle? For example, say they came ...
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Can the signs of charge of electron and proton be reversed? [duplicate]

I was thinking that the electron, proton, neutron etc. are human given names to some particles. So, are the signs, positive of proton and negative of electron, given just to show their opposite ...