# 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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### 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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### How does the Electric Field create a force? [closed]

If we have 2 charged particles which are a certain distance away from each other, they either attract of repel due to the electric field created by both of them. But I don't understand the mechanism ...
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### electrical field in coaxial cable

When getting the electric field between the outer and inner cylinder. why is it that we are only concerned with the field generated by the positive charge distribution on the inner surface and not ...
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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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"A charge that is accelerated will produce variable electric and magnetic fields. These are electromagnetic waves. If the charge oscillates with a frequency f, then the resulting EM wave will have a ...
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### What is the electric field at the midpoint of the hypotenuse of a triangle? [closed]

Given, AB = BC = a and Charges at A, B and C are +q, +2q and +q respectively. Found this problem in a textbook. I did it this way : Charges at A and C will have no effect at this point since electric ...
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### There is a hollow object where will the charges reside? Inside the balloon or on the surface of it? [duplicate]

There is a hollow object (for example an inflated balloon.it is charged. where will the charges reside? Inside the balloon or on the surface of it?
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### Magnetic force on a charged particle doesn't affect total energy

So there's this sentence in a book I am reading. It states "When a charged particle is placed within a magnetic field, despite the magnetic force acting on the particle, there will be no change in the ...
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### Principle of capacitor

It is said that second conductor reduces the potential of fist conductor and hence increases charge taking ability of first conductor My confusion... As per my limited knowledge it is electric field ...
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### how could Kinetic energy increase if no energy was there in the system?

i was reading Physics-Halliday, Resnick, Krane(fifth edition) there on page 638 it is written: if the external agent does positive work in assembling the charge ...
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### Charge Magnitude Based on Isoline Spacing

Suppose we have two positive charges of unknown magnitudes. We are given the isoline map (the equipotential lines) for the two-charge system. One has isolines more "squashed together" (more closely ...
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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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### Conductors, charges and method of images; Intuition?

Two charges e and -e are placed at distances d and 3d, respectively, above an infinite conducting plane (directly above one another). Find the force on the charge e. To Solve this I consider another ...
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### Understanding zero field inside a conductor?

Imagine a neutral conductor of any shape, the charges are randomly distribuited among the object. No way we can say the electric field inside is zero. If I'm wrong, then what can we say about the ...
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### Which way is the magnetic field headed? [closed]

Question Is the magnetic field directed into the page or out of the page? I am using this right hand rule --> RHR So anyhow, my index finger is pointing downwards, and since the magnetic force is ...
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### Force of Electrostatic Attraction between 2 rings

Before someone puts it on 'hold' , this is not a homework question, I doubt you'll find it somewhere as I thought of it. I wish to find force of electrostatic attraction between 2 uniform rings of ...
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### What is the charge density for line and surface charges?

In electrostatics it is common to see line, surface and volumetric charges being described differently. A line distribution is a function defined on the line, a surface charge distribution is a ...
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### Electric Flux in a Gaussian Surface

Why is electric flux of a charge everywhere inside a Gaussian Surface constant? I want explanation ( not from any equation ).
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### What is the relationship between potential energy and electrical potential?

I actually always thought this was trivial, now I am not so sure. For a potential $\phi$ the potential energy is $V=q\phi$ where q is a test charge. Now I am thinking this may work differently in two ...
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### Dipole moment of a single point charge

Kindly refer to the Multipole Expansion section (chapter 3) of David Griffith's Introduction to Electrodynamics. Let us first discuss about why multipole expansion is needed. As far as I understand, ...
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### While deriving Coulomb's Law from Gauss' Law, the power of 'r' comes out to be exactly 2 while experiment shows that it differs about 10^(-16). Why?

While deriving Coulomb's Law from Gauss' Law, the power of 'r' comes out to be exactly 2 while experiment shows that it differs about 10^(-16). Why is it so? I'm referring to the book 'Physics by ...
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### Immersing a copper sphere into a conducting liquid that is itself in a conducting bath [closed]

Question A small copper sphere of radius a is half immersed at the surface of a poorly conducting liquid of resistivity $\rho$. The liquid is contained in a spherical copper bath of radius b, where b ...
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### Understanding electric potential in the context of gravitational potential?

I'm trying to understand the concept of electric potential and the significance of an electric field being related to the gradient/derivative of an electric potential. I found this question that ...
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### 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 ...
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### Calculating the surface integral over a charged box [closed]

In a question that I'm trying to solve, we're told that there is a box with dimensions 20cm long, 4cm high, and 3cm deep. we're given that the electric field on every surface of the box is pointing ...
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### Net Electrical Force

If a metal is insulated from earth and if a charged object is held near one end of it but not touched , will the net force acting on the metal be zero ?
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### Does a positive electric charge moves when it is placed inside a hollow conductor, but not in the center?

Electric Field inside a hollow conductor is zero. But what happens to a positive electric charge put inside.
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### Energy (voltage) correction on energy level between metallic electrodes with dielectric and accounting for work function difference

My goal is to understand how to correct for the field drop and the work function difference when performing electrical measurements on a certain energy level of a sandwiched system. The situation is ...
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### Coulomb's law and its application [closed]

I just read that Coulomb*s Law describes (a) the forces that bind atoms together to form molecules (b) the forces that bind molecules together to form solids. My question is Do a proton share ...
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### Can a grounded spherical shell have a charge?

Can a grounded spherical shell lying inside another bigger non-grounded shell have charge on it? If yes then why? Won't the charge on the grounded conductor flow to the ground?
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### Calculation of charged sphere distribution near a wall in Cartesian coordinates

I am following a similar derivation as found in the beginning of this paper "Quantitative aspects of the growth of (charged) silica spheres" by A.P. Philipse. This paper calculates the growth of a ...
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### How does electric charge flow in the typical experiment of scuffing your shoes across the carpet?

I'm trying to understand the flow of electric charge. I have read about the triboelectric series, but I do not know where the rubber soles of shoes and carpet reside to know whether the shoes acquire ...
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### Surface charge distribution on a conductor derived by method of images techniques

Kindly refer to "The classic image problem" of "THE METHOD OF IMAGES" of Introduction to electrodynamics book by Griffiths (Chapter 3). A point charge is placed at (0,0,d) on the z axis. The XY plane ...
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### Electric field inside a material

I was thinking about the polarisation, and how the electric field behaves inside the material of permittivity greater than one. I think to have understood what happens to D and P, but is not clear ...
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### Gauss law and electrostatic induction. Concentric spheres

Imagine you have hollow concentric spheres A and B with radius a and b (b>a), respectively. If A is a conductor and B has a certain density charge, I´ve been taught that B will induce some net charge ...
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### Electric potential and work

A unit positive charge $q$ is placed in an electric field caused due to a positive charge $Q$. $q$ experiences force of repulsion $F_R$. We apply an external force (FEXT) opposite to $F_R$. The test ...
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### Charged metal sphere- electric potential [duplicate]

Why is the electric potential on the surface of a charged metal sphere always constant?
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### Whats the meaning of this equation relating electric field and potential energy?

My electrodynamics teacher was explaining that it is required to apply some energy (or do some work) on charges in order to arrange them in space. When he stated an example about energy in a capacitor ...
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### 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 ...
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### I don't get the idea of potential in a capacitor [closed]

First off, what is meant by the potential of the conductors? Also potential difference between the two conductors is a function of distance from either right? Then why does it have an exact value. For ...
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### electrostatics and elecrtic field [closed]

two opposite charges are placed and thee electric lines of forces are drawn if the angle made by the tangent at the initial point of one charge is 'a'then find the angle made by the line of force that ...
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### Force on a charged conducting sphere due to a uniform electric field

If a charged conducting sphere is placed in a uniform electric field , will the force on it be simply qE ? I know that the electric field lines enter a conductor perpendicularly so does this have any ...
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### Electric potential inside a shell

Inside a shell, electric field is zero. Then does it have a constant electric potential inside the shell? If $V=\dfrac Ed$, then since field is zero, potential should also have been zero. Please ...
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### Electric Field Vector on an insulating solid ball

An insulating solid ball with radius $R$ has a uniform charge density $ρ$. Find the electric field vector inside and outside of the ball if it has dielectric constant $K$. Normally, I'd treat this ...
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### Does wearing a metal hat does increase your chance of being struck by lightning?

Does wearing a metal hat does increase your chance of being struck by lightning? Prompted by this video. My view is that it makes no difference as to the conductivity of the head or the field ...