Tagged Questions

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

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When two like charges are placed at a large distance from each other, do they attract each other? [closed]

So my friend and I were arguing about this. He insists that if two like charges are placed at a large distance from each other, they attract each other. I find this nonsense. This clearly violates ...
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Why is it easier to remove stains with water?

And I don't mean stain removers, but literally tap water. See here's the thing, you can't remove a stain without some sort of friction, and water reduces friction. Yet if I say, spill some coffee and ...
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Magnitude of charge on each plate of a parallel capacitor? Why should I multiply by two?

Here's the full question: A parallel-plate capacitor has a plate area of $0.2\ \mathrm m^2$ and a plate separation of $0.1\ \mathrm{mm}$. To obtain an electric field of $2.0\ 10^6\ \mathrm{V/m}$ ...
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What does potential mean in capacitor?

Technically potential means work done to move a unit positive charge from one point to another against electrical field but What does potential mean in a capacitor?
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Relationship between electrons (leptons) and quarks

I assert the following is true: Either: electrons are made up of (two) quarks Or: Quarks are made up of some kind of smaller particles, which also make up electrons. I think this must be the case ...
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Electron losing its charge

If the electron is said to be a charge carrier, then could it lose its charge ? It wouldn't remain an electron ofcourse , because charge is one of its important properties . But am talking about the ...
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Reversibility of uniqueness theorem

If we use uniqueness theorem then we know that if the boundary conditions and the charge distribution is same in 2 setups in a certain region then the electric field and potential in that region in ...
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Flow of charge through metal wire [closed]

It is the flow of charge that matters -- electrical current is defined as the flow of charge. " -person W [...] if the flow of charge is all that matters; and electrons with their charge attached ...
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Why are there e.m. vacuüm fluctuations?

According to the rules of qft there are virtual photons in the vacuüm. But how can this be if for the production of photons you need an electric charge?
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Why are electrons negetively charged? [duplicate]

Why have we assigned a negative charge to electrons (and positive for protons)? I feel it would be easier if electrons were positive (thereby, protons negative)- electrons would flow in the direction ...
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What exactly is Breakdown Voltage of Air?

Most of the online sources say that the breakdown voltage of air is 30kV/cm. I've made a Cockcroft Walton multiplier and I can see the air breaking in between 17-18kV/cm. Only in a discussion at one ...
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Why is there no negative mass? [duplicate]

We know that the entire matter has a property called mass. Charge is also a property of matter. If negative charge can exist, why don't negative mass exist? Also, like charges repel each other. Then ...
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What are all charge-like quantum numbers?

What are all charge-like quantum numbers? In particle physics there are often things (like charge conjugation) that apply to all charge like quantum numbers. Everytime I read something about charge-...
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Potential energy of a shell & point system

Consider the system of a point particle with charge $q$ and a spherical shell with uniform charge $Q$ and radius $R$ whose center is a distance $r > R$ away from the point particle. I'm trying to ...
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Charge distribution parametres

I'm reading an article regarding charge distribution parametres in muonic atoms ad I'm stuck in the very first pages. In particular, I don't understand, given a 2-parametre Fermi charge distribution ...
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Why is it said that electric current always flow from higher potential to lower potential?

Why is it said that electric current always flow from higher potential to lower potential? It is said that current flows from positive terminal to negative terminal, but it is actually the negative ...
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Gauss's law, electrical flux density [closed]

Q. Given a 60-μC point charge located at origin, find the total electrical flux passing through the plane z = 26 cm. I can understand what the question means, but I can't do anything. Is it using ...
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Choosing between a parallel-plate and spherical capacitor model

This problem is solved in the solutions manual by making reference to equations for the parallel-plate capacitor. I have some basic understanding of why this is the case (the local curvature is small ...
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What is the difference between emu and esu?

Ok...so this is the statement given in my book: a) In C.G.S System the unit of charge is electrostatic unit of charge (E.S.U). It is also called Stat Coulomb (StatC). b) In C.G.S system, the unit ...
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Electric potential energy of a charge

Potential energy is the work done by the particle against a conservative force. Isn't it? when a charge is fixed on a free space and then when we bring another charge from infinity to a distance r ...
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Charged conducting wire ring and Greens function

ρ(r) = q 2πa2 δ(r − a)δ(cos θ). If this is my charge distribution on a conducting wire ring. radius=a. I am attempting to show my electrostatic potential as an integral along the z-axis I started by ...
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Why do they rub rubber with wool while glass with silk and not otherwise?

why not the other way round, and why do they choose wool and silk in particular to charge the rubber and glass rods ?
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Why does adding more components in parallel increase the current?

Why does adding more components in parallel increase the current? Shouldn't the charges be more distributed, so they can't 'push' each other at the same rate anymore?
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Method of image charges — Why is a *grounded* plate needed?

In the classic image charge problem of a charge $q$ above an infinite grounded plane, it is well known that the field lines essentially behave as though there were a negative charge behind it, and the ...
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Why charge is not a measure of inertia?

We know that mass is the measure of inertia of rest. Then why charge is not a measure of inertia? What causes the difference between charge and mass?
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What's the relation between representation theory and mass / electric charge?

This is a follow-up on this answer, where ACuriousMind wrote Formally, both the mass and the charge classify certain irreducible representations of the Poincaré group and the circle group, ...
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Force on a charge due to charged sheet

I want to find the force on a positive charge placed at a distance $d$ from a positively charged infinite plate. Of course, it can simply be done by finding the electric field due the plate using ...
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The charges of the forces

I am trying to establish a simplified understanding of the fundamental forces to explain them to a young audience. If we say that gravity has one charge (attractive), electromagnetism has two charges ...
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Are objects generally neutral or charged?

Basically the questions relates to what is taught about electroneutrality and has 2 parts: Is the overall charge in the universe zero? Are objects the world generally neutral or slightly charged, ...
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Electric flux of a charged rod through a uniform disc

I have an assignment regarding electric flux. The question I was given has the following sketch: The first question was about the force on the rod from the disc at the $z$-axis. I reached the ...
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Thought process [closed]

Voltage = Energy/ Charge If voltage comes out of the negative terminal through a wire to do the powering and then end up at the positive terminal, then what is it that comes out the positive terminal....
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Electrostatic potential due to angular dependent spherical charge distribution

Problem: Given the charge density $\rho = \rho_0 \frac{r}{a}\sin{\theta} \sin{\phi}$ for $r<a$, and $0$ for $r>a$, calculate the electrostatic potential. Issue: I have previously done a ...
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How to discharge a plastic surface? [closed]

In a plastic sheet surface, how to make the surface charge disappeared ?
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Charge moved across a potential difference; where does the energy for emitted radiation come from?

Let's use an electron and a 1V potential difference as a mode. In school I learned that if the electron is at the negative end of the electric field, its potential energy is equal to the work that ...
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Magnetic Field in parallel plate capacitor [closed]

A parallel plate capacitor of area 60cm^2 and separation 3mm is charged initially at 90 micro coulomb. If the medium between the plates get slightly conducting and the plate loses charge initially at ...
Consider a charge of 1C kept a distance of $6*10^8$ m from a detector. I find electric field due to this charge at detector. Then, I suddenly earth that charge and not the time it takes to be ...