Questions tagged [charge]

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

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Voltage Between Two Oppositely Charged Spheres

I can't figure out the parametric solution for the voltage U between two oppositely charged spheres with magnitude q that have radius r and the distance between their surfaces is d. With q = -1x10^7 C,...
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Follow-up on “Conservation of electric charge in Feynman diagram”

I took the following Feynman diagrams from page $5$ of this document: For the right diagram, I drew the circled $1$ and $2$ myself. What I unfortunately don't understand yet is: (i) This question is ...
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Why is charge density of copper always positive? [closed]

I found that charge density of copper is $8.491 \times 10^{28} \:\rm carriers/m³$. I got this in google: Charge carrier density of copper Because copper has only one free electron per atom, its ...
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Charge on parallel cylindrical conductors with reverse current

Suppose one has two parralel cylindrical conductors with a distance $d$ and an radius of $\rho$ while $\rho \ll d$ and length $l$. The currents through the conductors are reverse, but the absolute ...
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Origin of particles at the Big-Bang

When we read writings on the Big Bang, in Planck's time (and even for some who try to imagine what was before), one talk about particles and antiparticles, but where do these particles and their ...
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What happens if a positive charge and a negative charge meet?

If charge cannot be created or destroyed, then how do charges neutralise each other? do they both just become uncharged particles?
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I don't know how to how to solve this question [closed]

Here, I am sharing a question from chapter: electrostatics of Mathew Sadiku . I have tried a lot to solve this question but I am not able to solve this question. I would be thankful if someone helps ...
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Electric potential plane with periodic surface charge density

let a plane xOy with a surface charge density $σ(x)= σ_0 + σ_1cos(\frac{2πx}{a})\:\:\:\: σ_1,σ_0$ and a being positive constants the electric potential has the form $V(x,y) = V_0(z)+V_1(z)cos(\frac{...
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Relation between radius of curvature and charge density

As we know in electrostatics, a metallic surface is equipotential and any charge residing on it miraculously enough distributes itself such that the conductor becomes equipotential. The surface charge ...
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Charge distribution on a solid metal hemisphere (qualitative description needed) [closed]

Question: If a charge +Q is given to a solid metal hemisphere in absence of any external field then how will the charge be distributed on its surface. My answer: the charges will only be present on ...
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What is the force system?

Spring Force = $F_s$ Charge Force = $F$ If the system is balanced Based on Newton's Law On the horizontal line Is it $2F_s = F$ Or $F_s = F$ ?
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Capacitor with intially having charge $q$ on both plates and then battery connected

What would happen to capacitance and other quantities like Voltage if I initially take a Parallel Plate capacitor with each plate having equal charge "$q$" and then connect it to a constant ...
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Volume charge density in an imperfect conductor connected to an AC circuit

My goal is to understand whether or not there would be a source term $\rho$ in the Helmholtz (or Poisson) equation for the scalar electric potential, for the region inside an object with finite ...
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Does scaling the charge also scale the charge density?

In Griffiths' Introduction to Electrodynamics, 4th ed., he motivates the notion of capacitance by arguing that the electric field $\bar{E}$ is proportional to the charge, and hence so is the potential ...
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Understanding attraction and repulsion between 3 charges

Quoting Feynman from Chapter 2 of his book Six Easy Pieces (emphasis mine): Suppose that we have two unlikes that attract each other, a plus and a minus, and that they stick very close together. ...
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Flow of electrons [duplicate]

Why do electrons flow from lower potential to higher potential? According to the first law of thermodynamics, energy flows from higher to lower potential spontaneously. Electrons do contain energy but ...
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From where does an electron get its charge from?

I have read often that charge, like mass, is an intrinsic property of an electron. But even the mass is due to its interaction with the Higgs Field. So is there something which explains where the ...
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Why is the charge of electron not taken as negative when calculating the electrostatic force between the nucleus and electron in Bohr's model of atom?

In one of the postulates of Bohr's model of hydrogen atom it is said that "While the electron revolves, the electrostatic force between the electron and nucleus provides centripetal force. The ...
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Why the Earth isn't negatively charged? [duplicate]

As electricity is transferred in earth by earthing and lightning, why it does not become negatively charged?
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Why is the electric field in a homogenic electric field always the same?

When there is a charge between two parallel plates why is the sum of both forces always equal where ever it stands between those two plates? When I say both forces I mean the negative side ...
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Capacitance of a dipole antenna

let's see this evaluation of a dipole antenna capacitance. Here my reference. The text states that: The key assumption is that the electric field lines from one arm of the dipole antenna to the other ...
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3answers
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What is the correct order of integration when summing up the potential of a charge distribution? [closed]

The task is: A thin rod extends along the z axis from z = −d to z = d. The rod carries a charge uniformly distributed along its length with linear charge density λ. By integrating over this charge ...
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1answer
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Is the maximum possible charge on an object asymmetrical with regard to polarity?

I am not a physicist so I am not sure how to check my intuition. Hence my question here. Suppose I wish to charge a sphere to the maximum extent. Intuitively I imagine the following: I can give the ...
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1answer
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Some doubts regarding electric field inside a hollow shell made of charges

This question is a follow up to this question. Here my doubt is about a shell made up entirely of charges. I am asking this question because all physics and electrostatics/electrodynamics books talk ...
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2answers
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Electric field inside a non-conducting shell with a charge inside the cavity

I have read about conducting charged shells and spheres and know somewhat about the electric fields associated with them. But I have never found anything on non-conducting shells. I have searched ...
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What happens inside the shell cavity when we charge a conducting spherical shell?

Let us take a conducting spherical shell with no charge on it initially. Now if we put a charge $+q$ on its surface (by either method of induction or contact), would charges be induced on the inner ...
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What is the induced charge distribution on inner surface of a symmetrical conducting shell when a charge is placed off-centre? [closed]

Let us assume that we have a symmetrical conducting hollow shell with a charge $Q$ on its surface. Now let us bring a point charge $q$ inside the shell cavity and place it at any point except at the ...
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Can we differentiate if point charge is rotating or not?

First, sorry for the low level English and physics knowledge. Point charge. If point charge is not possible, let me use ball charge. The ball charge is same in all directions. (Symmetric) It's maybe ...
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How the atoms of a negatively charged plate of a capacitor accommodate extra electrons?

Let suppose the capacitor's plates are of aluminium and someone has charged it so that one of the plate is positively charged and the other is negatively charged, also the capacitor is not connected ...
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Charge on infinite planes at zero potential

I am looking for some help with a problem of Electrostatics. Let us consider three parallel conducting slabs $P_1, P_2, P_3$ of a certain surface $S$, small thickness and mutual distance $d$. We know ...
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Is voltage just the energy created from the separation of charges?

Recently learnt some physics, and I just want to check my understanding
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How to make a specific vertical electric/electric displacement field

I wanted to try to make a sphere (with net charge $q$) float with electrical force so I applied the fact for the ball to be at rest the net forces to be 0. I assumed the only other force than gravity ...
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What precisely and mathematically does it mean to have $W$ bosons carry electric charges?

What precisely and mathematically does it mean to have $W$ bosons carry electric charges? We know from Wikipedia that experiments say that $W$ bosons carry electric charges: $W^\pm$ carry $+$ and $-$ ...
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Eletrical Field created by a charge surface on a point [closed]

I was answering this question and even tho i know intuitively that the radial component of the eletric field will cancel out by simmetry, i could not get that in the integral calculation. I´m asking ...
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Why in non-uniform polarisation of dielectric we take net charge density to represent charge inside the dielectric?

I have two doubts, First is why we use term net charge flow out of volume instead of positive charge like in case of uniform polarization and the charge $Q$ in eq 10.21 is net charge of volume element ...
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How are Components of Electric Field Calculated Based on a Graph?

I have been stuck for the past few hours on how to correctly calculate components of an electric field, specifically the y component for a certain graph. Here is the problem, which is followed by my ...
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Universe with only exactly two charges of the same sign

I am trying to understand the cosmological consequences of having a Universe with non-zero total charge. For example, an infinite, unbounded universe with a finite total charge and thus zero charge ...
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Relativistic Inertial Reference for Charged Particles

Suppose two elétrons separated by a distance that their mutual interaction is so weak that can be regarded as null. Suppose also they are under the effect of a constant and uniform electrical field ...
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Does surface charge contribute in polarization of the dielectrics? [closed]

If yes, exactly how does the surface charge contribute in the dielectric polarization?
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Getting the current density of a wire with given surface charge density [closed]

I found this question, which seemed very easy to me at first, but when I revisited the problem I started to have some doubts about my approach, so I would appreciate any form of discussion or approval ...
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Why is the electrostatic force felt in straight lines?

When two positive charges are kept close, they get repelled in the direction of a line joining both the charges. Why is it so? Also, why is the repulsion in a straight path? In both the cases, the ...
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Would the charges in a current-carrying wire move to the centre of the wire due to attractive magnetic force?

We know that the magnetic force acting on two parallel wires carrying current in the same direction is attractive. I am wondering: Say we have a thick wire carrying current, with initially the same ...
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Confusion about the sign of $e$ in scalar QED

It has been pointed out in a previous post that the convention used for the gauge covariant derivative tends to be different in nearly every textbook. As was pointed out in this excellent answer, ...
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Usefulness of electric field

I've solved many problems calculating the electric field, $E$, of a given charge distribution but I'm just musing a bit as to why this is useful. The definition of $E$ involves the force, $F$, on a ...
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Can a massless particle have both spin and charge?

Can a hypothetical elementary particle, at least in theory (according to the current science), have 0 mass and yet also have both spin and electrical charge (at the same time)?
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Why Coulomb's Law is only valid for point charges?

Why Coulomb's Law is only valid for point charges? Is there any reason? Why this law is not valid for other charges rather than point charges?
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Is this a valid way to show an infinite sheet of charge has a uniform field using Gauss's law?

From a pre-academic studies book, the example uses a gaussian surface outside of the charged sheet to show that because the flux through it is 0, the field on both ends has to be equal. Is this a ...
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Why electric potential definition demand the positive sign of test charge?

Why does electric potential definition need to distinct a positive test charge since the result will be the same even with a negative test charge? We could define electric potential with agnostic sign ...
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When do travelling (accelerating) charged particles emit radiation in their direction of travel and when perpendicular to their velocity? [closed]

I have read numerous things saying that a travelling charged particle emits radiation primarily in a cone in the direction of travel, and other places say the radiation is emitted and polarized in an ...
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Electrostatic induction - how to quantify it with a theoretic integral expression or like?

Assume that a certain distribution of charges $\rho$ generates an electrical field $E_{ext}$ in the surrounding space. We also note the corresponding generated potential $V_{ext}$. Assume furthermore ...

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