All Questions
Tagged with electricity electric-current
791
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The temperature of a metal wire rises when an electric current passes through it because- [closed]
The options given were-
A)Collison of conduction electrons with each other releases heat energy
B)When the conduction electrons fall from higher energy to lower energy level heat energy is released.
C)...
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1
answer
69
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Does all the Energy provided by the battery dissipate into heat?
Before proceeding onwards please note that I am talking about a simple circuit consisting of an ideal battery, a switch and an external resistance.
So I was told that $$ W_\text {ideal battery} = Q_\...
- 93
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40
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Confusion about EM waves in a conductor, AC in wires, and skin effect
I am trying to get my head around these different points:
From Maxwell's equations we find that an electromagnetic wave in a conductor decays in amplitude with a characteristic length of about 1 cm in ...
- 197
1
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1
answer
111
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Derivation and theory for $I = kV^n$ [closed]
I performed an experiment in college to study the nature of a filament of a lamp, determine $k$ and $n$ in the relation mentioned, and study the variation of wattage of a lamp. I assume ohm's law is ...
- 33
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1
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53
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Why is current through the short circuited wire not zero? [duplicate]
Why does current flow in a short circuited wire? I understand that it offers negligible resistance to the flow of charges, but two points on the short circuited wire will have the same potential, so ...
0
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2
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78
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Why doesn't charge accumulate in a loop?
When learning about electromagnetism at my university, electricity flow is generally shown as a conductor with a high potential at one end and a low potential at the other and thus charges flowing ...
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3
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6
answers
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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93
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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 ...
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50
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Why should the heating coil of a heater have high resistance?
In my book, it is given:
The resistivity of an alloy is generally higher than that of its constituent metals. Alloys do not oxidise (burn) readily at high temperatures. For this reason, they are ...
- 1,066
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38
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Force on charge carriers in a simple circuit
Is it true that in a simple circuit where a simple conducting wire is connected to a battery, the force on each charge carrier is same in magnitude ? If yes, then can you explain how? I know that if ...
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2
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Why does the power loss in transmission cable increase when resistance is increased?
In transmission cables, why does power loss increase when length of conductor is increased? According to the formulas V=IR and P=I²R, When we increase the length, the resistance increases, while the ...
3
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3
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126
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Current density of moving charge distribution - mobile charge density vs. "ordinary" charge density of the distribution?
in Introduction to Electrodynamics by David J. Griffiths I have latched upon this definition of current density vector $\mathbf{J}$ (Chapter 5, section 5.1.3, p. 220 in 4th edition) and I would ...
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2
answers
55
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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 ...
- 21
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41
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Do electrons move faster towards the end of a circuit?
As 1 coulomb electrons go through 1 volt of potential difference, they gain 1 joule of energy. So in s series circuit, do electrons move faster towards the end of the circuit where they went though a ...
5
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2
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135
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What is the "closed circuit" of a bug swatter racket?
There are bug swatter racket that can kill fruit flies, mosquitos, or flies, if the insect touches the metal mesh.
However, when I look at the construction of the device, the metal mesh is all one ...
- 151
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34
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Is there electric field inside the conductor in moving charges case?
Is there an electric field inside a conductor when steady current passes through it ?
I have two conflicting notions here : I was watching this Electroboom video and at minute $14:00$ electroboom ...
- 441
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6
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317
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Why is current defined as $dQ/dt$ even though it is not defined as the rate of 'change' of flow of charges?
I do not understand this definition. $dQ/dt$ represents the rate of CHANGE of charge flow at an instant even though current is defined as only the charge flow per unit time.
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431
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Direction of electric field and current [closed]
What is the direction of electric field in electric circuit is it positive to negative or negative to positive? Is the direction of current same as the field?
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52
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How current flows in an ideal wire? [duplicate]
what are the assumptions that we make, that should be kept in mind when a current is flowing through an ideal wire of 0 resistance? And what is the speed of the electrons in an ideal wire? if I have a ...
-1
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2
answers
107
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Potential Divider Circuits
Consider the following circuit:
From my understanding, consider the series circuit without the $V_o$ part. The voltage must be used between resistors $R_1$and $R_2$. We know $V=IR$ from ohms law. As ...
1
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2
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192
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Why chemical energy is doing the work on the electrons to move them from cathode to anode and not some kind of force?
We say that in an electrolytic cell the redox reactions occuring on the electrodes are exothermic and that chemical energy does work on electrons to move them from cathode to anode and this work done ...
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1
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38
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Ideal Superconductor connected to Zero Voltage
If an ideal superconductor was just left alone, with no potential difference, what would be the current flowing in it?
According to Ohm's Law, $V = IR$
Hence, if a superconductor of $0\Omega$ ...
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1
answer
134
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Why electric currents in equal and opposite direction cancel each other?
I know that electric current is a scalar quantity and hence it should not follow vector addition. But I have read that equal currents in opposite directions will cancel out each other so is this kind ...
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2
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60
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Why electric charge does not gain net energy in closed circuit?
In a text book, when they calculate power dissipated in a closed circuit, they use circuit with a battery and one resistor. Idealized positive charge travels from +...
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1
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78
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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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61
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Why do we indicate current to be flowing against electrons in a electric circuit ? If it is a convention thenwhy do we draw it along studying it? [duplicate]
I believe that electric current is a kind of force (even when we consider it to be opposite to the flow of electrons). If it is so then what is the nature of this force ? And also tell me if there are ...
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2
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86
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In a metallic conductor, during the electric current, do the electrons flow from one end to the other or they just vibrate
Do the electrons cover the entire path of a circuit during electric current or they vibrate or oscillate at their positions?
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74
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Why does the current flow through a wire if the wire is an equipotential surface? [duplicate]
From what I know, current flows across two points only if there is some potential difference across those two points. If that is the case, why does the current flow through a wire then?
See the ...
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1
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44
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Why current density is defined?
I feel that the reason to define thing like current density is that we want to use the directional nature of the current like a vector quantity and since electric current is not a vector so we define ...
- 131
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2
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54
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Piece of iron instead of a proper fuse
In a video game Dying Light 2, there are those electrical boxes that you open and then "fix" by putting a piece of iron (I suppose). Assuming voltage $U$ is being produced and is supplied ...
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