# Tagged Questions

Electrostatics is concerned with the electrical fields and scalar potentials of stationary electrical charges and charge distributions. Use this for questions about electromagnetic situations in which currents and magnetic fields are absent, otherwise use [tag:electromagnetism] and/or [tag:magnetic-...

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### How does electrostatic force affect electronic devices?

How does electrostatic force generated by two seperate plates having opposite charges affect electronic devices? I know that magnetic fields have some harmful effects to electronic devices but I am ...
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### Insulating cylinder with charge in a uniform electric field

Suppose that we have a very long insulating cylinder of radius $R$ on which we have placed some electrons such that it has a constant $\sigma_0$ charge per unit length. Assume that we then apply a ...
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### Two charged spheres connected with a conductor

I have a problem with a electrostatics problem: there are two spheres, each one of the same size carrying the same amount of charge, but of different sign. They are connected by a conducting wire, ...
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### Why can't charge be in a stable equilibrium in electrostatic field?

I am reading Feynman's Lectures volume_II where he discussed the impossibility of the presence of stable equilibrium in an electrostatic field. There are no points of stable equilibrium in any ...
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### Electric field inside two parallel lines of charge

At what force will a particle be subjected to inside two parallel line charges with the same length and charge density. I get that in the middle the forces will cancel, but will they cancel if the ...
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### How to calculate the work of the electrostatic forces in a parallel-plate capacitor?

The expression of the energy stored in a parallel-plate capacitor is: $$U = \frac{e_0\cdot A \cdot V^2}{2d}$$ with $e_0$ the vacuum permittivity, $A$ the surface of the capacitor, $V$ the applied ...
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### Potential at the surface of a conducting sphere near a dipole

An ideal conducting solid sphere of radius $R$ and center $O$ is brought near a dipole with a dipole moment of magnitude $p$. Let the center of the dipole be called point $C$, and let the tangent from ...
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### What is the method to find field at the center of a conducting shell due to induced charges due to an outside charge? [closed]

For example, if we had to find the field at Q1 due to the induced charges on the outside spherical surface ,what should be our approach? According to me, as the induced charges due to q2 on the ...
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### What does the Dirac delta function physically do while deriving Gauss Law form Coulomb's law?

While doing this derivation, the the source coordinates are mentioned as "$s$" and the coordinate of the point at which field is to be calculated is mentioned as "$r$". Kindly follow this Wikipedia ...
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### Basic concepts of electrostatics

How to deal with a grounded conducting sphere (I.e finding charge on it) in uniform electric field ? And if any two charged conducting spheres are in each other's electric field then will ones field ...
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### Current in discharging capacitor through fixed resistor?

In the textbook I'm using for physics it says that the charge left on the plates of a capacitor after time $t$, that is discharging through a fixed resistor, is $Q=Q_0e^{-t/\tau}$ where $\tau=RC$ is ...
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### How to show mathematically that the electric field inside a conductor is zero?

The electric field is characterized by the equations $$\nabla\cdot \mathbf{E} = \dfrac{\rho}{\epsilon_0}$$ $$\nabla \times \mathbf{E} = 0$$ Or equivalently, $\nabla^2 V = -\rho/\epsilon_0$ and then ...
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### Dielectric sphere placed in another dielectric medium with uniform external field: is there a surface charge density?

Consider a dielectric sphere placed within a dielctric medium. There is a uniform electric field $E_0$ present throughout in the medium. Would there be surface charge on the sphere?
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### Electrostatics-Coulomb's Law

Coulomb's Law is an experimental result. The furmula that Coulomb found to describe electrostatic interactions is: $$F=k_e\frac{q_1 q_2}{d^2}.$$ How did or What did Coulomb do to verify this law as ...
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### What is meant by short circuit in capacitor?

I can't understand the mechanism of short circuiting in a capacitor. How will it come to know me that the capacitors are short circuited
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### How did physicists know that only negative charges move?

I have phrased similarly another question about how physicists knew that two charges exist, positive and negative. The purpose of the question is not necessarily to educate me historically. It's just ...
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### On touching the negative terminal of battery, shouldn't this negative charge flow to earth?

On batteries one terminal is clearly mentioned as negative. I wonder can we neutralize this terminal by just touching it with finger? In electrostatics it is common to neutralize a charged object by ...
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### The image current due to moving charges and a current carrying thin wire

Suppose we have a plane conductor and positive charged particles of mass m are moving parallel to the plane conductor at a distance d. The trajectory can be assumed to be straight. An image current ...
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### Spherical Conducting Shells, Potential

When we have a spherical conducting shell and charge on outer surface of the shell then the potential inside remains constant i.e, kQ/R (R=radius). But say the inner surface of the shell is charged ...
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### Static electricity and insulators

I've read that Stephen Gray in his experiments on electricity, he has found that static electricity can be conducted -transferred- through an insulator thread made of silk. So, how could that happen ...
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### Is the electric force a vector or a vector field?

The electric force (Coulomb's law) on a point charge $Q_2$ due to $Q_2$: \begin{gather*} \mathbf{F}_{12}=\frac{Q_1Q_2}{4\pi\epsilon_0}\frac{\mathbf{r}_2-\mathbf{r}_1}{|\mathbf{r}_2-\mathbf{r}_1|^3} \...
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### Static electricty and fields inside of the conductor?

I have a few related questions about static electricity and conductors. 1. when we say static electric field inside a conductor is zero, let us take an example of two concentric conductors, outer one ...
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### Photon as a gauge boson for static fields

Excuse me if my question is naive, but I have never taken a proper QFT. I used to think of a photon as a quantum of EM field, quantum of light. But form QFT and particle physics prospective, photon ...
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### What exactly is electric dipole moment & how it works?? and Why Electric Dipole Moment vector's direction is from negative charge to positive charge?

What exactly is electric dipole moment & how it works/used? (don't go into deep mathematical calculations) Please answer the question about the direction with good details. Don't just say that it'...
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### Mistake calculating electrostatic potential energy formula!

I have a problem calculating the electrostatic potential energy. I rely on these equations coming from mechanics: U_{B}-U_{A} = -W_{A \ \rightarrow \ B} (done\ by \ the \ field \ ...
682 views

### Boundary conditions in Electrostatics

If I have a grounded conducting material, then I know that $\phi=0$ inside this material, no matter what the electric configuration in the surrounding will be. Now I have a conducting material that ...
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### Is potential difference the difference in electric potential energy or electric potential?

Referencing the book Physics for Scientist and Engineers, Ninth Edition, the book says that "Potential Difference should not be confused with Difference in Potential Energy." I also reviewed several ...
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### Charge distribution on a Gaussian surface

In the text, it is said that the skewed distribution of positive charge on the inner wall cannot produce an eletric field in the shell to affect the distribution of charge on the outer wall. Why? ...
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### How does a conductor shield the outside from its inside

If I have a charge of $+q$ placed arbitrarily within the spherical conducting shell, by Gauss' law, the E field produced will be created outside the shell, as if the charge were placed at the center. ...
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### Electric field in a hollow object

I am currently visiting a course about electrodynamics. In my last lecture it was said that if a hollow sphere is inside of a bigger sphere, but only in the bigger sphere there are spherically ...
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### Why does there have to be an electric field if there is potential difference?

I read in a few books that there is always an electric field if there is an electric potential. I went through this but the question on this page only states that there is an electric field and it is ...
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### How did physicists know that there are two kind of charges?

Problems The question I am about to make is either too stupid or hasn't bothered anyone because its obvious because I can't really find the answer anywhere. I am currently studying electricity and ...
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### Symmetries of non-parallel infinite conducting planes

Suppose I have semi-infinite conducting planes that intersect at some angle $\theta_0$ and have a potential difference of $V$ (the axis of intersection is somehow insulated so they are not actually in ...
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### Name of electric force

during a lab experiment, i noticed that a metal ball has a much harder time rolling on metal rails when their is a current passing through it and the rails. I was wondering why and if there was a name ...
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### Electric field of a line charge, along itself

look at the pic : What is the electric field in along the line of charge with charge density $\lambda$ and length $L$. Is the electric field zero along the line without any difference in height?