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Questions tagged [conductors]

For questions about materials which allow the flow of an electric charge (electrical conductors) or the transfer of heat (thermal conductors) through them.

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1answer
297 views

Difference between bound and free charge/current in a perfect conductor

For the case of charge, it seems clear that in a perfect conductor the free charge refers to the excess charge that has been dumped into the conductor, while the bound charge refers to the charge that ...
6
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4answers
733 views

Can a positively charged conductor have negative surface charge density somewhere?

This is a simple question that occurred to me while thinking about electrostatics. Let's consider a positively charged isolated conductor in equilibrium. In general, the surface charge density varies ...
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2answers
46 views

Magnetic force between two long conductive wires with current

I was asked to calculate the total magnetic force between two long conductive wires with current on them, flowing in the same direction. I used the formula F$_1$=$μ_o\frac {I_1I_2l}{2πd}$ and got a ...
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1answer
49 views

Direction of magnetic field lines around a conducting wire

By way of the first uploaded picture I was taught that magnetic field-lines around a long conducting wire with a current are shaped like concentric circles around the wire. However, a few pages ...
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1answer
63 views

Is diamond able to conduct electricity given 5.5 eV of energy? How do we then identify insulators and semiconductors?

I have learnt that the band gap for diamond, an insulator, is $5.5\:\rm eV$. Does this mean that diamond is able to conduct electricity if we give it this immense amount of energy (let's assume we do ...
2
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1answer
364 views

Reason for gold being the most malleable and ductile of metals

I understand how fcc structure enables plastic deformation in metals, but why is gold, in particular, the most malleable and ductile of fcc metals? Is there something about the electronic structure ...
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1answer
971 views

What happens to potential when a charged body is placed next to an uncharged conductor?

I know that the potential of the charged body decreases due to induction however I feel as though I need a more in depth answer. Why does induction cause the potential of the charged body to decrease ...
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1answer
105 views

derivative of the electric field along the normal to the surface near the conductor

how to derive the formula approves the derivative of the electric field along the normal to the surface near the conductor is inversely proportional to the principal radii of curvature? $\frac{\...
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2answers
73 views

What actually happens during metallic conduction?

My book mentions that when an electric field is applied to a conductor the electrons get accelerated in a direction opposite to that of the field. These electrons however collide with the atoms on the ...
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2answers
75 views

Does electric current create positive ions while flowing through a conductor?

As the conduction electrons are free to move randomly, i.e they are not restricted to a particular atom, then why don't these atoms get positive charge due to loss of these conduction electrons?
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4answers
87 views

Question on direction of electric field

My physics textbook (1st year university course on Electrostatics) mentions that when looking at a positively charged metal disc from the side, the electric field is located perpendicular to the ...
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3answers
222 views

Electric shielding skin depth

I read that lower the frequency,the deeper is the skin depth in conductor.If we are using piece of thin conductor,like aluminum foil for example to shield something from electric fields,it would ...
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1answer
49 views

Why there is no charge within the conductor even if the charges are static?

"When excess charge is placed on a solid conductor and is at rest, it resides entirely on the surface, not in the interior of the material. �" Source: University physics 13th edition p(736). ...
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0answers
59 views

Eletric potential outside a conductor sphere [closed]

During my chemistry graduation, my Physics III professor gave to us an exercise that would worth an adition in the final mean. Well, I've finished the graduation, and the exercise was forgoten until ...
-1
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1answer
116 views

What happens if I place a charge inside a hollow conductor and fix it? [duplicate]

So I know that when you put some charge inside a counter, it resides uniformly on the surface of the conductor in order to make the electric field zero everywhere inside the conductor.. But what if I ...
4
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0answers
73 views

Skin effect fully explained by plane wave attenuation?

I went over the explanations of the skin effect in multiple sources. However, I still don't understand how the fact that this equation: \begin{equation} (\Delta - \mu_0\sigma\partial_t - \frac{1}{c^2}...
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2answers
179 views

How is voltage proportional to current?

The question came up in another forum - "What causes current to flow". Many knowledgeable people explained that what causes the flow of charge are electric field forces or Coulomb forces. If there is ...
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2answers
59 views

Some questions regarding electric properties of materials [closed]

I was reading Chapter 29 on Halliday-Resnick-Krane regarding this but couldn't understand these things. Suppose you have a conductor in an electric field. In normal conditions the field inside the ...
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4answers
558 views

Car hit by a lightning strike

In Griffiths' Introduction to Electrodynamics, at the Electrostatics chapter, in particular, in the conductors section, he says this after the stating that within an empty cavity surrounded by a ...
3
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1answer
64 views

Does corrosion of metals depend on electron degeneracy pressure?

Corrosion is about losing electrons for the corroded metal and gaining electrons for the oxidising substance. Is it correct to assume that what controls this process is the electron degeneracy ...
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0answers
113 views

Is the electrostatic condition $\vec{E} = \vec{0}$ in a conductor something to be accepted?

The usual explanation goes as follows. Charge flows until the applied electric field is canceled by the induced field, giving a total field $\vec{E} = \vec{0}$. This is reasonable if one gives as an ...
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4answers
981 views

Work done by magnetic field on current carrying conductor

Suppose a wire of length L carrying a current I is kept in a uniform magnetic field B perpendicular to the current. The force on the wire will be IBL and work done by magnetic force when wire moves a ...
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2answers
470 views

Is there a way to make infrared pass through metals?

I am curious to know a way that will make infrared pass through metals. Metals are good reflectors of infrared,can we manipulate the wave in order to make them pass through metals?.
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2answers
485 views

What is drift speed in electricity and how is it related to the cross sectional area of the conductor?

In fluids dynamics, I learnt that as rate of flow is constant for an ideal fluid, Area(cross sectional area of the tube) x velocity is constant.I had a doubt whether the same relation exists between ...
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0answers
11 views

Effect of humidity on removing excess charge from objects [duplicate]

The usual answer to the question "why electrostatic discharge happens more often on dry days" is that water - due to its polarity - has the tendency to remove the excess charge. But I do not ...
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1answer
27 views

Ways to generate long-lasting charge on materials surface?

First off, I am no physicist, please don't judge me if I said something wrong. I read that insulator surface can carry a static charge by rubbing against another insulator with a different electron ...
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0answers
14 views

Applying Gauss's Law on a Non-Uniform Conductor [duplicate]

I've seen tons of examples of Gauss's Law applied to solve for electric field. However, the only shape its ever really applied to is a cylindrical or spherical Gaussian surface. I'm looking at a ...
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3answers
201 views

Non-zero electric field inside a conductor, when applying an large external field [duplicate]

I'm probably missing something, or does not understand conductors well enough. But I have a question related to the title of this message. In many places you read that there can be no electric field ...
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0answers
250 views

Charge distribution on Spherical conducting shells

For example we have very thin conducting spherical shells of radius R and 2R. Initially the smaller shell has Q and other shell has q charge of their own, now there will be charge induction in them ...
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1answer
38 views

Can the graphene's conductivity be explained using only orbitals?

I am trying to find a 'easier' or more 'intuitive' way to calculate the conductivity of graphene. I want do this by using atomic or molecular orbitals. Anyone have a clue about how this can be done? ...
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1answer
362 views

Derivation of drift velocity [duplicate]

In my textbook, it is given that drift velocity $$v=(eE/m)t$$ where $t$ is the relaxation time. But this is the maximum velocity an electron achieves before collision and hence the average velocity ...
-1
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1answer
36 views

Can we infinitely charge a hollow metal sphere? [closed]

I know this isnt practically possible due to dielectric breakdown of the surrounding medium but otherwise ...what would be the outcome? Following is the link of the question which came up for me in a ...
-3
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1answer
554 views

why is electric field inside a conductor zero? [duplicate]

I know that the net electric field inside a conductor is zero due to field made by induced charges. But , IS IT NECESSARY ? what i mean is that what would happen if the net electric field inside a ...
2
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0answers
51 views

what is the current operator of an interacting electron gas?

If i have an electron gas with coulomb interactions, what would be the current, operator. I would write the Heisenberg equation of motion for the density operator, than write the continuity equation ...
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0answers
29 views

Exact distribution of electric field in conducting current carrying cylinder

Consider a conducting cylinder, whose place surfaces are connected to a battery. Now, if we assume electric field inside it is constant, and electric field just outside it is zero, then circulation of ...
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1answer
39 views

Capacitors electic field

If we have the electric field on the surface of a conductor being $E=\sigma / \epsilon_0$ where $\sigma$ is the charge per unit area then why is the combined $E$ field from two parallel plates not 2x ...
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1answer
397 views

Electric field in asymmetric conductor configuration

I was trying to figure out an electrostatics exercise. I am confortable solving these type of problems, when there is an easy application of symmetrical properties and Gauss's Law. But this one took ...
1
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1answer
171 views

Charge Distribution on Conductor - Uniform or Not?

Consider a hollow conducting spherical shell S1 inside an irregularly shaped conducting wall S2 (in the figure). The sphere S1 is somehow given a charge +Q. Will the charge distribution on S1 be ...
-1
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3answers
107 views

Current, conductors and charge density

Ok i read that the charge (current) entering the conductor is same as that of charge leaving through the conductor Means current is same at all the points in a conductor having varying cross section....
0
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1answer
52 views

Mechanism of electricity in conductors

In mechanism of electricity in conductors my teacher said the free electrons collide with positive lattice and this positive lattice is oscillating about its mean position. Ok for producing current ...
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1answer
92 views

Mechanism of Electricity(current) Through Conductor

i encounter the concept of conductors first in electrostatics. In which they said that the electric field lines cannot pass through the conductor. The reason they give is there is an opposite electric ...
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1answer
72 views

Capacitance due to accumulation of charge on the interface between resistors

It is well known that the continuity condition for current density necessitates that at a steady state: $$\frac{\rho}{\epsilon_0}=-\frac{E\cdot \nabla \sigma}{\sigma}$$ Where $\sigma$ is the ...
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1answer
21 views

Charge on surface [duplicate]

I have read that the charges in a conductor at most can move to the outer surface (unless provided a conducting path) and cannot go to the outer insulating region. My question is which force stops ...
0
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4answers
112 views

Couldn't the electric field in a conductor be non-zero at points of zero charge?

In electrostatics, it's often claimed that we can assume the electric field inside a conductor is zero. The way I interpret this claim is: If we have a region containing charge which can move ...
-4
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1answer
567 views

Factors affecting Capacitance

In case of a parallel plate capacitor, I knew that capacitance is affected by area, separation between plates and dielectric medium. so am I right with the idea in the given picture?
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2answers
99 views

What is the cause of opposite electric current direction of flow of current inside a battery?

My question is that why the direction of current inside a battery is different than that of outside battery?Can someone explain how current is even carried inside a battery because free electrons aren'...
0
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1answer
230 views

Why does the graph of the electric potential of a conducting sphere look like this?

The graph of the electric potential of a conducting sphere with radius $R$ is curved when $r > R.$ Since the electric potential outside the sphere is $k\frac{Q}{r},$ shouldn't the graph be linear ...
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2answers
112 views

Two field form of the Maxwell equations: Why are effects due to polarisation ignored.

I have a couple of questions regarding the following section in my notes and would like some help in resolving some confusions. 1)why is εr = 1 in the plasma? 2) If µr = 1 it means we switched off ...
1
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1answer
220 views

Does the drift velocity of an electron in a wire with constant current depend on the area of its cross section?

Suppose current, $I=nevA$ with the electron density $n$, the cross section of the conductor $A$ and the drift velocity $v = \frac{V}{RneA}$ where $R$ is the resistance of the wire. This equation ...
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1answer
1k views

What is the complex conductivity of a metal?

I was told that it is possible to describe frequency dependent properties of metals in terms of the equations of motions of the charge carriers. In order to do so the Drude model can be exploited and ...