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2answers
82 views

Why Electric field inside the spherical shell is zero? [duplicate]

electric field in and out of the spherical shell Why the field inside the conducting spherical shell is zero? Professor Lewin said and I quote," there is NO charge inside the conductor because any ...
0
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1answer
53 views

How can electrons travel from the valence band into the conduction band?

I'm currently studying Introductory Semiconductor Device Physics by Parker. In band-theory, we know that if an electron is at the top of an energy band, then there are no allowed states immediately ...
5
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2answers
163 views

How far do electrons actually move along a conductor under an alternating current?

This is more or less a curiosity question. But I have had really good luck with stack exchange so far. If I can expand on my question a little bit - it may not be super important, but I know under say ...
0
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1answer
36 views

Does “charge density” account for all charges, or only negative charges, and do opposite charges cancel each other or add?

if I had 10 electrons and 8 protons in a meter cubed would the charge density be 2 or 10 or 18? I suspect 10, but I don't see why charge density only takes into account the negative charges. another ...
2
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1answer
224 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 ...
0
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2answers
71 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 ...
0
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1answer
46 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). ...
3
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1answer
60 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 ...
-1
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3answers
86 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 ...
0
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1answer
20 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 ...
1
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2answers
59 views

Current in a conductor

In electrostatic shielding, we have read that the charged particles in a conductor experience no force. In the current carrying conductor, electric field is applied across its ends and the ...
0
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0answers
126 views

Relation of carrier density to number of valence electrons in metals

In the classical Drude model, we find that the electrical conductivity of a metal is given by $$\sigma = \frac{ne^2\tau}{m} $$ where $\tau$ is the relaxation time, $m$ is the electron mass and $n$ is ...
24
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6answers
4k views

Speed of electrons in a current-carrying metallic wire: does it even make sense?

Does it make sense to speak about the speed of electrons in a current-carrying wire (non perfect conductor)? If so, what is their speed? Here are my thoughts: On the Internet (Wikipedia, ...
3
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3answers
2k views

Is current the speed of the electrons?

My teacher got me really confused this time. He said that current is the rate of flow of charge. If this is true, then current could be the speed of the flow of charge (ie. the kinetic energy of the ...
0
votes
1answer
38 views

Is the speed at which electrons move through a conducting wire binary?

If a voltage differential causes electrons to move through a conducting wire, and no other forces are acting against them, will they always move at the highest possible speed through that material? ...
0
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1answer
98 views

Best visualization of electric current and voltage

I asked this exact question on the electrical engineering stack exchange, and it was suggested that I post it here: So, I want to know what the best way to visualize what is actually happening in a ...
1
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2answers
64 views

Does a battery actually provide electrons or are they the electrons in the wire moving due to potential difference?

When we connect a battery in an electric circuit, does it provide the electrons present at anode, or are they the electrons present in the wire?
4
votes
1answer
247 views

How do electrons actually move in a wire? [duplicate]

Do they jump from atom to atom or are they free-flowing? Where does resistance fit in? Do electrons physically HIT the atoms? If so, how do they hit atoms if the nucleus is small and far away from the ...
0
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1answer
30 views

Is there twice the amount of current in semiconductors than that in conductors (at same temp.)?

In semiconductors unlike conductors where $e^-$ move from lower quantum states to higher quantum states in conduction band, electrons move from Valence Band to CB and create 'holes'. These holes add ...
0
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1answer
268 views

Why don't insulators attract even if charged?

I understand that/ obviously, opposite charges will attract? However, I am still slightly confused about what happens if an insulator becomes charged. How come an insulator, which is charged, will ...
3
votes
1answer
175 views

How the current moves in the battery and outside the battery?

Does it move again to the negative terminal or stays at the positive terminal until the electrons all come .so the voltage will.be zero and current flow .I want simple clear explanation because i am ...
0
votes
1answer
146 views

What is electric current? [closed]

I have been reading a book about electricity which states that: electric current is not the movement of electrons but the "impulse generated when free electrons orderly "jump" from one atom to the ...
3
votes
2answers
355 views

If energy delivered to the resistor is not the kinetic energy of the electrons then how is it delivered? [duplicate]

In a help session by Walter Lewin he says that the energy delivered to the resistor is not the kinetic energy of the electrons. If not how is energy delivered. The video link is https://youtu.be/...
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1answer
404 views

Speed of electrons in a wire

What is the speed of electrons in a copper wire, used to charge a device? If there is a fixed speed, how is it determined?
10
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2answers
2k views

Do electrons move around a circuit?

We could imagine a simple electronic circuit composed by a power source and a resistor. It is usual find descriptions as "The moving charged particles in an electric current are called charge ...
21
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5answers
4k views

Why don't free electrons escape from a conductor?

The thermal velocity of the free electron in a metallic conductor varies from $10^5\ \mathrm{m/s}$ to $10^6\ \mathrm{m/s}$. In spite of high velocity, free electrons fail to escape from the metallic ...
1
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2answers
173 views

How the current flows in a circuit? [duplicate]

If the electrons and protons are moving in a circuit, then they should cancel each other after crossing the barrier? How is it working?
0
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1answer
2k views

How can electrical conductivity of pure water be increased?

I know that impure water(containing salts) or acidified water can conduct electricity but pure water is a poor conductor of electricity. So is it possible? Please explain.
3
votes
2answers
559 views

How is the speed of electricity determined?

Before I am told this is a duplicate, I'd like to be specific here. I have searched online for an answer regarding the speed of electricity in general and haven't found what I'm looking for. Even in ...
4
votes
2answers
317 views

Why do electrons follow the conductors shape?

I'm stuck thinking about this situation. I imagine that there are two oppositely charged objects at short distance $r$, put inside an insulator (Can I say air?). They generate a net elctric field, ...
0
votes
1answer
483 views

What is the difference between atomic density and intrinsic concentration?

If a Si sample is doped with boron impurities in the ratio of 1:10^6, it means that for every 10^6 Si atoms, 1 boron atom is added. I have been given information that atomic density of Si is 5*10^22 ...
0
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1answer
1k views

Intrinsic semiconductor having less conductivity than extrinsic conductor

The question is quite simple.Why intrinsic semiconductor has less conductivity than extrinsic semiconductor? I want to know the exact doping concentration per atoms in extrinsic semiconductor relative ...
7
votes
3answers
624 views

Voltage as electromotive “force”

Considering the "water analogy" for electricity, it seems voltage is sort of like gravity: (image source: http://learn.olympiacircuits.com/electricity-flows-like-water.html) Now when water actually ...
3
votes
1answer
228 views

How far do electrons go in an antenna?

Do you know what is the distance electrons cover in an antenna during the production of a radio wave? Does the extension of the oscillation vary with the frequency or the power of the radiation? Is ...
2
votes
1answer
73 views

Do 2 conductors (1 grounded via resistor) reach equipotential, before surplus electrons drain to earth?

Case I: a negative conductor makes contact with a neutral conductor. Negative donates some electrons to neutral, until there is 0 potential difference. Then they both are slightly negative. This ...
0
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1answer
494 views

Confusion about charging a conductor positively or negatively

In my books,Principle of Physics(Grade XI),it shows the process of charging a conductor positively or negatively by induction.At the last picture,when the charge is completed it says'The positive or ...
2
votes
4answers
736 views

Charged non-conductor [duplicate]

A conductor is defined as it has free electrons to move, but when non conductor attain charge, it would also have free electrons. so it should behave like a conductor or not?
1
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0answers
26 views

Determination of electrons flow through the crystal

Talking about doped semiconductors: Atoms outer shell extends and overlaps with another ones outer shell (the conduction band), right? So when electrical field is applied to a semiconductor bar (lets ...
11
votes
2answers
8k views

Where do all these electrons come from? [duplicate]

I'm a high school student and I'm fairly familiar with basic electronics, but I've always wondered one thing. So how generators make electricity from motion is the move a magnet around or through a ...
3
votes
1answer
282 views

How do electrons move at an atomic level? [duplicate]

This was meant to be a sub question in the comments of my last question but I think it is big enough to have its own post. I know that electrons move because of the potential difference across the ...
-3
votes
1answer
310 views

How electricity works acutally?

I've been told that electricity is due to flow of charges(-ve charge=electron) that are provided by the battery. And no. of charges that leave battery at one end are equal to no. of charges that re-...
1
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1answer
153 views

Propagation of Electric Signal from Physics Perspective? [closed]

We know that in terms of copper or metal conductors, when one part is given heat the other part also gets hot. This is some kind of transmission of electrons. Signal transmission in terms of data ...
2
votes
1answer
149 views

What do the batteries actually do to the electrons?

I am plagued by this simple question that what force exactly causes the motion of an electron in the middle of a lattice of electrons of a wire? a. Is it an electric field created inside a wire due to ...
4
votes
3answers
4k views

Why electrons flow through a wire connected to a battery?

I would like to know why does electrons flow through a wire connected to a battery as said in AC/DC: What's the Difference?.It tells that "the electrons that are stripped from the carbon electrode is ...
2
votes
3answers
717 views

How can a parallel circuit work? [duplicate]

The electrons always takes the easiest way in a circuit, right? So in a parallel circuit, why does the electrons flow through all parts of the circuit and not just the one with the least resistance?
1
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2answers
838 views

Some questions related to circuits and flow of electrons

I have some doubts related to electric fields and flow of current. So, let us assume an electric circuit, which contains a battery and a wire connecting positive and negative terminal of the battery. ...
5
votes
4answers
4k views

Path of EM wave propagation in a circuit wire

The image is my visualization of drift velocity and electromagnetic (EM) propagation of charge wave in a closed circuit. The slow drift velocity of the electrons follows the path of the circuit (a ...
0
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2answers
174 views

Can a piece of metal have all of its conduction electrons stripped?

Can a piece of metal have all of its conduction electrons stripped? If so, has this been done and for what value?
0
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1answer
176 views

Putting an Electron on a Conducting Sphere [closed]

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