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

learn more… | top users | synonyms (1)

1
vote
0answers
39 views

Can a lightning strike cause your car to not run? [migrated]

If lightning strikes a tree in your yard and your car is close by, can this cause your car to not work properly? I had an employee call in stating that lightning struck a tree beside their mobile ...
-1
votes
1answer
24 views

Flow of charge through metal wire

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 ...
0
votes
1answer
48 views

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?
0
votes
0answers
25 views

Expressing charge density in terms of spherical multipoles

How to express the charge density in terms of the full set of the spherical multipole moments? That is, how to invert the relationship $$ Q_{lm}=\frac{4\pi}{2l+1}\int ...
0
votes
1answer
21 views

Is there a charge difference between ground and our head?

I commented on a question on Skeptics.SE that it would be an interesting question whether there is a charge difference between ground and our head. The question is not very relevant, but here it is ...
0
votes
3answers
34 views

Understanding Capacitors [duplicate]

I cannot understand how capacitors work. Electric field is supposedly uniform between the parallel plates of a capacitor. But how? Since $E=\frac{kq}{d^2}$, shouldn't the electric field approach ...
-4
votes
1answer
45 views

Why is it possible to produce electromagnetic waves using a charge and electric or magnetic field? [on hold]

Why electromagnetic waves can be produced by the motion of charge in electric or magnetic field? Explain.
-4
votes
0answers
26 views

Where is the net electric field 0? [on hold]

A positive charge +3Q is separated by a distance, d, from a negative charge -Q. What is the closest distance in which the net electric field is zero.
14
votes
7answers
1k views

Why is capacitance defined as charge divided by voltage?

I understand that capacitance is the ability of a body to store an electrical charge and the formula is $C=\frac{Q}{V}$. What I don't understand, however, is why it is defined as coulomb per volt. Of ...
1
vote
0answers
17 views

What is the potential difference between the plates? field around the plates? charge is on each plate? [closed]

What is the potential difference between the plates? field around the plates? charge is on each plate?
1
vote
1answer
30 views

How do I determent the radius and the viscosity of air on an oil drop falling? (Millikan's Oil Drop Experiment)

I bought this article with the intentions of learning how to do the calculations in Millikan's oil drop experiment. ...
0
votes
0answers
28 views

Electric potential inside a conductor inside another conductor [closed]

Suppose there is a neutral hollow conductor body $B_2$ and there is another hollow conductor $B_1$ inside $B_2$ . Let there be a charge $q$ on $B_1$ . Let the potential inside $B_2$ but outside $B_1$ ...
1
vote
1answer
69 views

Electric Flux is zero

When is the Electric Flux zero through a closed surface? I know that if number of field lines entering is equal to leaving then it is true. Which I think is always true for a closed surface. So can ...
0
votes
0answers
34 views

What is the definition of electrical charge? [duplicate]

In one simple sentence what is the definition of charge as I don't understand what role it has in a circuit. Thank you
2
votes
1answer
32 views

What is maximum energy we can extract from electric field?

I was reading Does Electric field has mass Energy; it gives energy density k stored around an electric charge as $ k = \dfrac{q^2}{r^4}$ in skeleton form without any constants. So, a definite amount ...
0
votes
1answer
24 views

Motion of an electric charge within an electric field with two electric charges

Assume that air resistance and gravity are negligible and the only significant force acting in the scenario is the electric force. There are two electric charges, both with an equal and positive ...
0
votes
0answers
23 views

How is corona discharge different from regular electricity ? [closed]

Since corona discharge is a electrical discharge is it any different from regular electrcity in terms of its ability to travel through wires, create magnetic fields , etc.
4
votes
3answers
60 views

Spherical Shell with Electric Field Zero Everywhere Inside It

If an isolated, charged spherical shell has a uniform charge distribution, the electric field everywhere inside it is 0, by Gauss' Law. Is the converse true? That is, given an isolated, charged ...
2
votes
2answers
42 views

Do Weyl fermions carry electric charge?

Do Weyl fermions carry ordinary electric charge? That is, do they interact with, for instance, electrons or photons?
0
votes
1answer
35 views

Surface density charge, divergence of the electric field and gauss law

It´s known that the divergence of the electric field at a certain point is given by this formula: $$\nabla \cdot E=\dfrac{\rho (r)}{\epsilon_{0}}$$ Being $\rho (r)$ the volume charge density at that ...
0
votes
1answer
52 views

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 ...
1
vote
0answers
13 views

Laws of electrolysis and quantisation of charge relation [migrated]

The quantisation of charge was first suggested by the experimental laws of electrolysis discovered by Faraday I think about it a lot but could not find any relation, as the number of electrons ...
1
vote
0answers
25 views

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 ...
0
votes
0answers
59 views

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 ...
0
votes
1answer
40 views

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 ...
0
votes
0answers
11 views

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 ...
0
votes
0answers
9 views

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 ...
-2
votes
1answer
36 views

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 ...
-1
votes
1answer
43 views

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 ...
0
votes
0answers
20 views

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 ...
1
vote
1answer
38 views

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 ...
0
votes
2answers
14 views

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 ...
0
votes
0answers
42 views

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 ...
0
votes
0answers
17 views

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 ?
1
vote
3answers
37 views

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?
1
vote
0answers
32 views

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 ...
1
vote
3answers
76 views

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?
0
votes
0answers
33 views

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, ...
0
votes
0answers
35 views

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 ...
1
vote
1answer
46 views

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 ...
1
vote
1answer
44 views

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, ...
-2
votes
2answers
81 views

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 ...
0
votes
0answers
32 views

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 ...
1
vote
1answer
17 views

How to discharge a plastic surface? [closed]

In a plastic sheet surface, how to make the surface charge disappeared ?
1
vote
3answers
51 views

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 ...
1
vote
1answer
64 views

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 ...
0
votes
1answer
33 views

Applicability of coulombs law for objects in different dielectric media

Is the Coulombs law applicable for inter-medium interaction? Consider the example image shown below How can one deduce the angles the bobs might make if they are in different dielectric ...
3
votes
2answers
97 views

Has such experiment been performed before?

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 ...
2
votes
3answers
94 views

What is a charge? [duplicate]

If mass is the measure of the inertia of a body, then what is a charge? Everyone tells that it is a fundamental property but i believe it must have a unique definition. Anyone know in this regard?
3
votes
2answers
37 views

Electric field due to a charged irregularly shaped balloon

There is a question in my textbook that says: A rubber balloon is given a charge $Q$ distributed uniformly over its surface. Is the field inside the balloon zero everywhere if the balloon does not ...