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

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Electric field radiation with moving charge and observation point

I've been working on Chapter 34 of the first volume of the Feynman Lectures on Physics http://www.feynmanlectures.caltech.edu/I_34.html#Ch34-S1. In Fig. 34–3 (reproduced above) Prof. Feynman shows ...
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1answer
18 views

Help with this question (Eletric Fields, Dipole)

The answer in the textbook in the solutions manual is the following: I didn't undestand the last step. He said he did a binomial expansion, I just can't figure out! Appreciate any help.
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1answer
27 views

Putting an Electron on a Conducting Sphere [on hold]

What all might go on inside a conducting sphere if I (try to) dump an electron upon it?
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1answer
24 views

Is it possible for a conductor initially, not to have a charge?

Well I'm confused. The thing that was implanted to me is that when I hear about conductors, some charge is present and it can move freely. Now what I want to know is that is it possible for a ...
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2answers
83 views

Why do charged objects attract pieces of paper, but not pieces of metal?

I do not understand one concept in Physics: why charged objects (eg. a charged rod or comb) attract pieces of paper when brought close to them, but do not attract pieces of metal. I know that the ...
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1answer
40 views

Levitating capacitor

As the title already says, I would like to make a large capacitor levitate. Before you dismiss this question please hear me out: In essence, this is intended to be a way to avoid the constrains of a ...
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2answers
39 views

Why do we get electric shocks when most structures are insulators?

Suppose I was standing in the sea, and touched an electric fence; I would receive an electric shock, because both my body and the sea are conductors, and create a path for the electricity to flow. The ...
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0answers
14 views

Will charge transfer without friction

I know rubbing two objects of different materials together will result in a negative charge on whichever material has a higher electron affinity. However, I was wondering if a negatively charged ...
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1answer
47 views

Simple question regarding Gauss's electric law

I just read that electric flux=enclosed charge/permittivity. Considering the charge in an enclosed surface is always 0, what is the point in even having this equation? Or is the equation actually ...
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1answer
202 views

What will be effects of harnessing lightning?

In Feynman's Lectures, volume 2, chapter 9, there is a mention of earth getting charged by thunderstorm lightning. It is the thunderstorms throughout the world that are charging the earth with an ...
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14 views

Calculating the rate of electrostatic charge loss

Let's say we have a hollow cylinder with no top and bottom and with a charge $q$, radius $r$ and height $h$ that is made out of hard rubber whose electrical resistivity is $10^{13} \Omega /m$ at room ...
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1answer
80 views

Why cannot massless particles carry charges? [duplicate]

How to show that massless particles do not carry charges from QFT's point of view?
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1answer
25 views

Can we charge any two bodies (insulators) by rubbing?

I am not talking about the usual glass rubbed with silk rather any two insulators found in nature. If we rub them, will they get charged? Like cotton and plastic etc.
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26 views

Why does flux in closed surface remain constant if exterior charge is altered?

Q. Charges $q_1$ and $q_2$ lie inside and outside respectively of a closed surface $S$. Let $E$ be the field at any point on $S$ and $\Phi$ be the flux of $E$ over $S$. One of the answer is: if $q_2$ ...
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4answers
52 views

Voltage - Energy drop

I'm having a hard time understanding the nature of voltage and am hoping you guys can help. The main issue is the concept of the voltage drop. Take the following circuits : In regard to the first, ...
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3answers
47 views

Drawing the lines of force for an electric field varying in magnitude but having a constant direction

How will the electric lines of force look for an electric field varying in magnitude but having a constant direction, say along +ve z axis ? According to me, since the electric field is varying in ...
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1answer
20 views

Capacitor and Pith Ball experiment

Suppose I first charge a capacitor so that one plate is positively charged and another negatively. Now I remove the charging source and ground only one of the terminals say negative terminal, will ...
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2answers
59 views

Rate of flow of electrons in a simple circuit, given the current? [closed]

I have this question: The correct answer is C. I understand that the flow of electrons should be from Y to X because electrons flow opposite to "conventional current", which is from positive to ...
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1answer
19 views

Surface charge on a straight region of a conductor

Most physics textbooks and even questions in stack exchange answer the question why there exists a charge buildup in the bends of a current carrying conductor. But what I am unable to understand is: ...
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2answers
40 views

Force on non-moving charge in solenoid with increasing magnetic field

The problem: "Through a solenoid there is an increasing magnetic field $B$. For a positively charged particle not in motion, what is the direction of force on the particle?" Normally a non-moving ...
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1answer
45 views

Charge of $W$-bosons in Feynman diagrams

When looking at Feynman diagrams of particle decays, how would I be able to find out the charges of the $W$-bosons involved in the decay?
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2answers
38 views

Is this diagram in my textbook not constructed to scale?

Or am I having an illusion. Clearly, the distance from 6v to 4v is not the same as 4v to 2v. I know it should be based on: $V = k\frac{q}{r}$.
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1answer
24 views

How does the size of conducting sphere affect the distribution of charge?

I am doing my homework. One question gives individual charges on two spheres. And asks what the resulting charge is on each after touching. But one thing interest me is that in the answer key, it's ...
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1answer
18 views

Why can't objects made of insulating material “store excess charges”?

This is quoted from my textbook. I saw plastic objects before being able to store excess charges. For example, if you rub paper against a plastic pole. Both will gain charges. But in lab, I never ...
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1answer
14 views

Would an electroscope work if it were not in a glass container?

I'm reading about the gold-leaf electroscope and all the sources I've read show that the gold leaves are placed in a glass container. Is there something special about the glass, or would any container ...
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1answer
115 views

Principle of superposition and QED

For finding a net force on a charge when it is in influence of many charges we simply do vectorical addition of all individual interaction of that charge with others. That's what is principle of ...
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1answer
59 views

What are the interpretations of ampere's circuital law for a single moving electron?

I understand from Ampere's circuital law that when a current passes though any open surface with a boundary (a circular boundary, for simplicity), then limit of summation of the scalar products of ...
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0answers
19 views

Why is Ampere not a derived SI unit? [duplicate]

From my understanding, Ampere is amount of elementary charge per time. So, you should be able to derive it from mol, which is amount, and seconds, which is time. My question: Why is Ampere a base ...
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1answer
33 views

If you charge water will the evaporation rate change?

If you take away electrons or add electrons to a body of water will the evaporation rate be changed? (Even if it's brief or the effect is small)
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1answer
31 views

Are Cosmic Rays net neutral in charge?

As I understand them, Cosmic rays mainly consist of high energy charged particles. I began to wonder if they would eventually net charge the Earth and then assumed that they must come in roughly ...
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2answers
27 views

A circuit that is net charged

What differences would you measure if a circuit were significantly charged negatively? Would the resistance change? To be clear, I mean that excess electrons are added to the system. The circuit can ...
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1answer
82 views

Can the fundamental dimension of Electric Charge be Mass only? [closed]

After solving dimensions of electrical equations, I found out that the fundamental dimension of Electric charge is mass only. This also leads to the derivation of dimensions of other Electrical units ...
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1answer
40 views

Grounding a capacitor

When one of the plates of an isolated capacitor is grounded, does the charge become zero on that plate or just the charge on the outer surface become zero?
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1answer
53 views

Force Acting on a Charge Between Parallel Plates

When a charge (say positive) is placed between an upper positively charged plate and a negatively charged plate, it should experience a repulsive force from the top plate and an attractive force to ...
2
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1answer
110 views

What happens to charge during laser ablation in water?

One of my friends from lab makes gold nanoparticles in the following manner: He puts a gold plate in water (without surfactants or other additives) He fires laser at the plate After 5 minutes ...
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23 views

Variations in electric field of a light speed charged particle

From the question " Is there a travelling speed of for electric field? If yes, what is it?" I get to know electric field propagates at speed of light. What if a charged particle which creates this ...
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1answer
66 views

Derivation of magnetic force for a charge in motion relative to a wire (M. Purcell's Electricity and Magnetism)

I have a question regarding the derivation of magnetic force in M. Purcell and David Morin's Electricity and Magnetism. In the first part, they derived the force first by assuming that a charge q is ...
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0answers
18 views

How would a closed conductor with only 1 layer of (atoms/molecules) behave if a charge is placed inside it?

I have quite a few questions actually related to this . Is it possible to have such a situation practically? If theoretically possible, how would the system behave?
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0answers
18 views

Total current - differential equation [duplicate]

Consider the circuit below consisting out of a capacitor C and two identical resistors R. For $t<0$ the switch is open and the capacitor is uncharged. At $t=0$ switch is shut and the circuit is ...
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1answer
23 views

Is $\kappa_e$ caused by charge-carrier transport or electron transport?

$\kappa$ usually symbolises thermal conductivity, a material's ability to conduct heat. $\kappa$ can be expressed with other partial thermal conductivities: $\kappa=\kappa_e+\kappa_{ph}+...$ where ...
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1answer
59 views

Circuit with capacitor and two resistors - total current - charge - differential equation [closed]

Consider the circuit below consisting out of a capacitor C and two identical resistors R. For $t<0$ the switch is open and the capacitor is uncharged. At $t=0$ switch is shut and the circuit is ...
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0answers
31 views

How do scientists measure miniscule constants like the mass and charge and speed of an electron?

What can measure the extremely tiny mass of an electron? Is it through indirect means? The same goes for charge. The pull of a single electron must be infinitely small. And if one is to attempt to ...
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1answer
53 views

If Coulomb and Esu have different dimensions, why can we convert simply by 1C= 3*10e9 esu?

I was always told in school we cannot convert an apple into a potato, so we have to have the same dimensions on both sides. When converting coulomb to esu, we do not seem to bother with dimensions. ...
4
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1answer
63 views

Why is $U(1)$ special when defining global charges?

For gauge groups like $SU(2)$ and $SU(3)$ etc. we know that observable states such as mesons or baryons must be charge neutral. However, for a $U(1)$ gauge group we can have charged initial states in ...
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2answers
98 views

Why is the Electric Field Zero at this point?

In a Phet Lab simulation, which is all I have at the moment to do my learning on electric field forces, the point represented as colored on the diagram below is shown to have an electric field ...
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2answers
90 views

Force between two point charges moving parallel to each other

When we observe two point charges moving parallel to each other we can see two forces acting on each of the charges: the Coulomb force the magnetic force ($\mathbf{F}=q\mathbf{v}×\mathbf{B}$) ...
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1answer
30 views

What is the purpose of defining an electric field, and how to apply it?

So, I've been reading an introductory book to physics. I've gotten to the point where I understand Coulomb's law, and now the book is introducing electric fields. I'm having a hard time ...
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0answers
37 views

Calculating rise in water surface due to a charged capacitor

Two metal plates separated by a distance d & initially charged with charge +Q & -Q are kept so that it just touches the surface of a very large water tank as shown in figure a. Thus water ...
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2answers
186 views

Application of Coulomb's Law

I've just finished reading a section in a book on Coulomb's Law. I'm trying to practice the math a bit and came up with the following: Suppose you have two charges, -5uC ($q_1$) and 7nC ($q_2$). ...
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1answer
43 views

Can I get help with measuring particle charge using oscilloscope?

How can one measure particle charge using oscilloscope and op amp integrator circuit along with a capacitor and faraday cup. I am unable to figure out how to approach. I have the circuit ready but ...