All Questions
Tagged with electrons electric-current
238 questions
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About how to express the movement of electrons along a conductor
I'm not an expert and have only a short knowledge of electron.
I was looking up the operating principle of lithium-ion batteries and there was something I didn't understand about the way it was ...
2
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1
answer
32
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Doesn't charge carrier density depend on the charge of the metal?
Imagine a sphere and wire charged to $10 \ \text{V}$ is connected to a neutral sphere. There are more charge carriers on the $10 \ \text{V}$ sphere and wire, so surely more electrons flow through the ...
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2
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49
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Why doesn't the number density of electrons increase with increase in temprature?
It is said that for some increase in temperature of a conductor there exists only some decrease in the average relaxation time of electrons in that conductor due to increase of their thermal ...
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Replenishment of electrons in an AC wiring system, after disconnecting battery charger?
I was wondering when you have a system which begins of course with the source of AC Electrical current, are on an isolated segment of that system, say connecting a segment of the power grid to a house,...
4
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1
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129
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Current operator for Bloch electrons [closed]
I'm trying to understand why in some lectures or review (e.g. in QHE lectures by Tong, or in the review Topological Field Theory of Time-Reversal Invariant Insulators by Qi), they say (without a proof)...
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6
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299
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Why is current the same when batteries are connected in series? [closed]
I struggle to understand why the current remains the same in the circuit when batteries are connected in series.
Update
I can reason with it if someone can confirm the update.
If the speed of ...
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0
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26
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If someone moves with a velocity $v$, relative to a conductor carrying current $I$, will the current change with respect to the observer?
If someone moves with a velocity $v$, relative to a conductor carrying current $I$, will the current change with respect to the observer?
I feel that the drift velocity of current is independent of ...
2
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2
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95
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How could free electrons flow in a conductor? If electrons actually flow in a conductor, then won't the atoms of the conductor become unstable?
I've read in many physics books that electrons flow due to a potential difference across a conductor, and that the flow of electrons is opposite to the current direction. But, if electrons move from ...
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6
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2k
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Is electric current actually the flow of electrical charge?
In my high school, the definition of electrical current is "the flow of charges" but I have seen a video about how electricity actually works and it seems to me that electrical current is ...
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2
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96
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What is actually electric current? [closed]
Electric current is the rate of flow of charges (electrons) or the rate of flow of positive charge. Okay, I get it. But here's my question. The electron flows in the wire and then the current flows in ...
2
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2
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137
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Electric current density definition
I'm just wondering why the current density $J$ is always defined as the amount of electric current traveling per unit cross-section area $J = \frac{I}{S}$, and not per volume unit $J = \frac{I}{V}$ so ...
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Does temperature cause electrons to vibrate more?
I read in textbooks that the mobility of electrons is affected by lattice scattering caused by vibrations of the lattice and by impurity scattering caused by impurities because they disturb the ...
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27
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Electric field inside wire [duplicate]
So I m a high school student and I learned that electric field inside conductor is 0 when it is placed in external electric field due to induced Electric field inside.
How can electrons flow if E(net)=...
1
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3
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247
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Is current directly proportional to electron density?
If current $i$ is directly proportional to free charge density $n$, then this means that a greater charge density will lead to a greater current. But simultaneously, this will also lead to more ...
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5
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310
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What is current?
Keep it simple please, I am just a 10th grader aspiring to become like you guys and solve complex equations but as of now I came across the chapter current and it said that current is opposite to the ...
2
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1
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102
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(A10) If light is an EM wave, can it interfere with electrons in a live wire, leading to a change in the wire's current?
Here's my question: If light is an electro-magnetic wave, with oscillating magnetic and electric fields, wouldn't light interfere with the free electrons flowing (slowly) in a wire, as the electric ...
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1
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60
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What is the agent responsible for direction of current density $\vec{J}$?
This is the question:
Consider a current carrying wire (current I) in the shape of a circle. Note that as the current progresses along the wire, the direction of $\vec{J}$ (current density) changes ...
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4
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770
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Explaining Ohm's Law and Conductivity's constance at particle level [duplicate]
I always wondered since my late high school years, how increasing the voltage can simply be proportional to the flowing current in a resistance.
Given $$\ dU = Eds = \frac{F}{q} ds \implies U \propto ...
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2
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48
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Is increase in current speeding up the electrons or is it just focusing velocities of electrons in the same direction?
Current in a wire is defined as the amount of charge that passes through a cross-section of that wire in a single second. By this definition alone, it is clear that a current relies on the motion of ...
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1
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88
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How do the electrons in a current-carrying wire move?
How do the electrons in a current-carrying wire move? Do they move in straight line, zig-zag or randomly while attracted to the positive charge? Picture or video examples are welcomed.
1
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1
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131
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Galvanic cell - when do we get electric potential?
In the galvanic cell in this image (2nd one with salt bridge): Link
Before putting the copper wire into the solution, do the Zn metal electrons have potential energy with respect to Cu2+'s electric ...
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1
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184
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Copper wire - how electrons behave?
we know, copper has 1 electron on the last shell(smallest ionization energy).
we also know that in a copper wire (don't imagine copper wire with electricity, imagine no electricity exists), A cubic ...
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37
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The flows of electrons when the voltage is zero [duplicate]
As we understand, electrons can't be unmoving therefore electrons always moving or flowing. If the voltage is zero, where do the electrons move? Do they move everywhere?
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1
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79
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What exactly happens in a circuit after it gains potential energy?
When an electron moves across a resistor, it loses potential energy.
Now imagine a simple circuit (series connection) with the negative terminal having 10v as its potential and positive terminal ...
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3
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1k
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Does current make the full return trip?
In an AC system, the neutral wire is said to provide a return path for the current back to it's source. Given that the current is said to be alternating back and forth, how does this work, does the ...
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2
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245
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Flow of Electrons in Potential divider circuit
Take the above circuit. I'm trying to understand how current flows through this potential divider circuit. I used the following simulation to help me visualize this.
In the simulation the electrons ...
0
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1
answer
106
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Behavior of electrons in a resistor
Imagine a circuit with a constant voltage and no resistance. Every electron would gain the same kinetic energy as it moves from the negative to the positive terminal. If we add a resistor to the ...
0
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1
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53
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Potential Energy of an Electron inside a circuit [closed]
Why doesn't the electric potential energy of an electron decrease while moving in a circuit away from the negative terminal? This question is concerned with the drop in the potential energy of ...
2
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2
answers
300
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Is a moving electret considered a current, and would spinning one make a magnet?
If I establish a permanent electric charge on some volume of material (as in an electret) and then move that material through space — is that motion equivalent to a current in a wire?
Also, since a ...
3
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1
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754
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Is charge carrier density an intrinsic property of a material and is thus constant?
I was studying the equation $$I = nAvq$$
where $n$ = the charge carrier density, $A$ = cross-sectional area of the conductor, $v$ = mean drift velocity of the
charge carriers, and $q$ = the charge on ...
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2
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68
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What is a current?
I am confused. One GCSE video on YouTube says it is a flow of electrons around a circuit; while, my textbook says it is a flow of charge around a circuit, carried by electrons. Since charge can be ...
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3
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257
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Does speed of electrons decreases when they pass through resistance?
What type of energy does battery supply to electrons , as I read battery increases KE of electrons but in load if they lose it then speed will decrease and current will decrease after coming out of ...
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2
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169
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Can we make electron drift velocity faster than light by reducing area of resistor?
We know that $I= nqAV_d$.
Can we send high current ($I$) through a "fat wire" (more $A$) then reduce $A$ at the resistor so much that $V_d$ becomes faster than light in order to maintain $I$?...
0
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1
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205
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Motion of the electrons in a electric conductor when connected to a potential difference?
(I am a beginner in physics, so please forgive me if this is stupid.) Normally, under static electric state there is no resultant electric field existing inside a conducting material. But, when a ...
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1
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129
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Why is electric field larger in a resistor?
Suppose there is wire with 0 resistance and a resistor between them and that circuit is plugged to nonzero voltage source. Why is the electric field in resistor larger than of the wire? I want to ...
3
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2
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369
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What makes a lightbulb glow?
I am self-studying electricity and magnetism, and I am confused about a point.
I have learnt that the drift speed of an electron is extremely small. However, according to Drude's model, the electron ...
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1
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142
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Why were electrons chosen to be negatively charged? [duplicate]
Wouldn't it make more sense to call electrons positively charged because when they move they make electricity?
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4
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116
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Understanding the definition of current
I can solve almost all my textbook problems related to current electricity using formulas but it seems in the end, I don't understand what current is. The bookish definition of current is:
Current is ...
2
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2
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1k
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Does current decrease with frequency increasing?
Electric field accelerates electrons in wire.
Because of at least inertia, when the electric field (voltage) is applied, electrons will not instantly have some maximum speed, but will continuously ...
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1
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34
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How are the electrons able to overcome the significant force of attraction of the ions?
The cause of electrical resistance(in a metal) is electrons colliding with themselves and the positive ions. So if the electrons collide with the positive ions, how are they able to overcome the ...
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1
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71
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What is a cathode and an anode in general sense
i am totally confused and not able to understand the difference between cathode and anode
Cathode is defined as reduction point but why is its sign -ve in a terminal and different in a battery
Anode ...
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2
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293
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Does a higher voltage always mean a higher electric field strength?
In a step-up transformer, the output voltage is higher than the input voltage, while the output current is lower than the input current. Basically, since P = VI is conserved, the current has to ...
0
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1
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138
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Distribution of current on a wire
Imagine a cylindrical wire with current flowing through it. What paths do the actual electrons take?
My first thought is that the electrons only move along the surface of the wire; since that is where ...
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4
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378
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Understanding voltage, what is physically happening with the electrons?
The way I understand voltage vs current is that voltage is the potential energy (or force) of the current. And the current is the amount of charged electrons passes through a conductor at a point ...
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1
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39
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In Drude model of conduction, are electrons moving across the conductive object?
As I understood, Drude model explains an electrical current as a chain of momentum transfer between electrons; In this sense, does a single electron leave its atom and move forming the electrical ...
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1
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83
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Is there some relationship between circuit voltage and the speed of circulating electrons?
It is well-known that under an external electric field the work that a charge has to do to go from a point A to another point B is $w=-V_{AB}*q$, this is equal to $\int_A^B{-\nabla V·dl}$ which would ...
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1
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494
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Charge moving in uniform circular motion
If a charge $+Q$ is moving in a uniform circular motion with angular velocity $\omega$ the equivalent current produced is $Q\omega /2\pi$. (We consider this as a circular loop and put a counter to ...
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0
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Electrons crossection distribution inside a direct current wire
If electrons of a DC flow feel mutual magnetic field that should move them towards the center of the wire and in that case their accumulation in the center cause electric repulsion should there be a ...
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1
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41
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How would I determine the charge density of an active lava flow?
It is my understanding that in molten silicates, such as a basaltic lava flow, electrons are decoupled from solid state structures. If this is the case, as lava is flowing through a tube, how would I ...
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5
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2k
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Why didn't we change the conventional direction of current after discovering electrons? [closed]
The direction of current is taken to be opposite to that of the flow of electrons, due to the established convention that current is in the direction of the flow of positive charges. My question is ...