All Questions
Tagged with electric-current electricity
791
questions
-4
votes
1
answer
71
views
Is my simplified explanation of Volts vs Current correct? [closed]
I was struggling to find any meaningful difference between Volts and Current, when studying the basics of Ohm's law.
The sentences explaining Potential Difference, between the negative and positive ...
- 117
0
votes
1
answer
69
views
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
1
vote
1
answer
41
views
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
vote
1
answer
113
views
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
0
votes
1
answer
54
views
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
votes
2
answers
78
views
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 ...
- 3
3
votes
6
answers
2k
views
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 ...
0
votes
2
answers
93
views
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 ...
0
votes
1
answer
54
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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 ...
- 1,064
0
votes
1
answer
38
views
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 ...
1
vote
2
answers
123
views
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
votes
3
answers
134
views
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 ...
- 85
2
votes
2
answers
57
views
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
0
votes
1
answer
42
views
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
votes
2
answers
135
views
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
0
votes
0
answers
34
views
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
1
vote
6
answers
331
views
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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0
votes
1
answer
446
views
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?
0
votes
0
answers
52
views
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
votes
2
answers
109
views
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
vote
2
answers
192
views
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 ...
0
votes
1
answer
38
views
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 $0\Omega$ ...
0
votes
1
answer
140
views
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 ...
0
votes
2
answers
60
views
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 +...
- 307
2
votes
1
answer
80
views
(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 ...
- 23
0
votes
1
answer
61
views
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 ...
1
vote
2
answers
91
views
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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0
votes
1
answer
77
views
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 ...
0
votes
1
answer
45
views
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
0
votes
2
answers
54
views
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 ...
- 291
0
votes
2
answers
123
views
Current by change in position of charges
I have been thinking about the idea given below
Consider the following situation
I have a rod which has a mass $m$ and hence does have the virtue to perform work against the gravitational field of ...
0
votes
1
answer
33
views
Analysis of Current for infinitesimal time
Suppose we have a hydrogen atom and electron is revolving in a orbit around the nucleus. We have to find current due to the revolving electron.
Current = ev / 2πr
( e = charge of electron)
( v = ...
- 109
0
votes
2
answers
38
views
Mobility (Current Electricity)
I was reading mobility in current electricity and there it was written that the direction of conventional current due to positive and negative current carriers is in the same direction but I cannot ...
2
votes
2
answers
127
views
Is it necessary for circuit to be closed in order for current to flow?
In case of earthing, we attach a single wire to the earth and if some residual electrons remain in the instrument they flow to the earth until the potential of the instrument also becomes Zero. So if ...
- 187
1
vote
2
answers
56
views
Moving charges in a circuit [duplicate]
Current flow from positive to negative terminal in a circuit. But the charges which are moving in the circuit are the electron that is moving from the negative terminal to the positive terminal. Why ...
0
votes
2
answers
57
views
Current in a two capacitors system in parrallel
I solved this question and I got the values of charges on capacitors in figure B. But my question is charge on capacitors is getting redistributed,but how is it possible when potential difference ...
0
votes
0
answers
27
views
Can you measure different currents at different contact points for a volume of material made of two different metals with different conductivities?
My question is about the variation of conductivity in a volume of material and its effect on measured current. A volume is comprised of two metals joined symmetrically in a cuboid shape as in the ...
0
votes
2
answers
185
views
Explanation of Potential Difference
My question is to verify if my thought process below is correct.
So in a circuit the charge will flow (the current). When the charge flows there is resistance which is the collisions of the charge ...
- 37
0
votes
1
answer
68
views
Current flow with no resistance
Imagine a simple circuit consisting of a battery with potential $V$ connected to a resistor with resistance $R$ by a loop of copper wire with $0$ resistance. It is obvious that a current $I=\frac VR$ ...
- 366
0
votes
2
answers
207
views
Does current flow equally through the cross section of a wire in DC?
(Most Probably a duplicate, but I couldn't find it)
I have heard about 'Skin Effect' in AC, but currently Im only and only concerned about DC.
When current flows in simple DC circuit, does the current ...
- 1,305
0
votes
3
answers
119
views
Why won't the bulb light? [closed]
Here's what the marking scheme says: "Capacitor gets charged first and acts as an insulator/blocks current".
However, electrons flow from negative to positive, so shouldn't the electrons ...
- 93
1
vote
2
answers
92
views
Energy conversions in Electric furnace
Heating furnaces use eddy current to work, but I have a problem understanding something, what are the energy conversions that happen in the electric furnace? Is it magnetic->electric->thermal or ...
- 17
0
votes
1
answer
129
views
Effect of solenoid on iron core in ac and dc circuit [closed]
If i have 2 insulated coils and i wrap each one of them on a iron core (i have 2 seperate ciruits) if i add a dc source “battery” in the first circuit and an ac source in the second circuit would ...
- 17
0
votes
3
answers
102
views
Potential drop against internal resistance of cells in combination
Suppose two cells of emf and internal resistance e1, r1 and e2, r2 respectively are connected in series. The negative electrode of 1st cell is connected to negative electrode of the second cell. Why ...
- 1
0
votes
2
answers
76
views
WIll maintaining the ratio of 'Voltage/Resistance' violate Ohm's Law?
In an ohmic conductor if voltage and resistance are increased in a constant ratio, the current will remain same and if it remains same, won't it violate the Ohm's Law?
As because Ohm's Law states '...
1
vote
2
answers
50
views
Why doesn't coil in an Ac generator not get deflected in accordance to the flemming's left hand rule when current starts to flow through it [closed]
Why doesn't coil in an Ac generator not get deflected in accordance to the Flemming's left hand rule when current starts to flow through it.
When the coil is ...
0
votes
1
answer
26
views
Do attracted to electrode charged particles make current?
Consider a bulb with an anode. Cathode, is out of bulb.
Bulb is filled with gas.
Now, gas molecules are ionized by, for example external radiation.
Bulb should now contain "free" electrons, ...
- 361
0
votes
1
answer
36
views
Current in a Nonuniform Diameter Wire
According to the text Current depends on Area, but then in problems with a "nonuniform diameter" we say that the Current does not change even though the Area changes.
I think I understand ...
1
vote
1
answer
147
views
How do electric fields in circuits exactly work?
I have been introduced to circuits and told that an electric field, along with a emf provided by an external source (which can't be electrostatic), causes electrons to move. They follow the direction ...
1
vote
0
answers
47
views
Resistance across different terminals of a material of variable resistivity [closed]
I have seen many questions in my book trying to find Resistance across different materials of variable resistivity(by integration).
For example, consider the following :
I can find resistance across ...
- 265