Questions tagged [electrical-resistance]
The tag applies to electrical resistance and resistors. DO NOT USE THIS TAG for non-electrical resistance.
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Circuits: Determining the voltmeter in physics [closed]
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Why does current grow in $LR$ circuit? [closed]
What actually causes the growth of current in a $LR$ circuit? One thing I understood was that the abrupt change in current induces an emf in the inductor but I still don't understand how that leads to ...
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Do electrons build up at the entrance of a resistor? [duplicate]
There is a voltage drop between the start and end point of a resistor. How does it achieve this difference in potential? For there to be a difference in potential there must be difference in charges. ...
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Understanding surface charges on a resistor and what a voltmeter is measuring
In this video Veritasium points out some misconceptions about electricty and hints at surface charges generating the actual electric field within the wires, better explained by Professor Carlson here.
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Reactance of an Inductor
The following video here derives an equation for the reactance of a capacitor. I am trying to derive the equation for reactance of an inductor.
Given an AC voltage drop $V(t)=V_osin (\omega t)$ in ...
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If two inductors with different inductances are connected in parallel to a dc circuit, will they have the same current in them at steady state?
Can the current division rule be applied to the inductors in steady state ? Wouldn't they have the same current in them if they are ideal ?
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Mesh current analysis but with variable resistors [closed]
I can't seem to be able to introduce V0 here!
Here was my working out, using 3 mesh and 4 node equations. Only one mesh equation has V0 but it doesnt seem possible to introduce it into the rest.
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How do charge carriers "know" how much voltage to use for work in a specific component? [duplicate]
I understand the basic concepts of voltage pretty well, I think. However, one thing has been bugging me which I can’t seem to figure out.
How does a specific charge carrier "know" how much ...
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Calculation of the electrical resistance of an anisotropic conductor with spacially varying current density [closed]
Fist time posting here, so I apologize in advance for the terrible editing .
I am trying to figure out a way to calculate the total resistance of a rectangular structure with known spatially dependent ...
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Equivalent Resistance of the resistance network [duplicate]
For the below circuit, I'm tasked to find the equivalent resistance. My teacher used Kirchhoff's law to determine the resistance to be R_eq = 7R/5. However I get a different result using a different ...
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Voltage across a capacitor in a circuit [closed]
I'm trying to find the voltage across the capacitor when it is fully charged in the attached diagram, I haven't done a problem like this before and I'm quite confused on what I am supposed to do to ...
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How do I calculate the electrical resistance for a sodium chloride solution? [closed]
Im doing a paper on how the concentration of sodium chloride in water affects the electrical resistivity of the solution. My teacher told me that I may not be able to use $R = V/I$ for this as sodium ...
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Magnetoresistance and Ionic conduction in mixed conductors
I've been facing a question recently on ionic conduction and have not had much luck coming across resources to reference (if there are some please point me in their direction!)
In a mixed conductor ...
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Diode confusion
Consider the following diagram
Here, the diode is in forward bias, and allows current to flow. However, I am slightly confused why this is the case. A diode is defined to only allow current to flow ...
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What is the angular frequency $\omega$ in which the maximum current occur?
for a circuit which consist of an AC supply, an inductor, a resistor and a capacitor, the differential equation would be $IR+V_C-V_0 cos(\omega t)=-l\frac{dI}{dt}$.
Taking another derivative with ...
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How do non-ideal inductors behave in a circuit?
I cannot comprehend how
can we break a seemingly non-ideal choke coil into just a pure resistor and inductor in series according to the following solution of a question.
Considering the data in the ...
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$I²R$ loss in case of transformer
Suppose we have a 100 V A.C. supply, and we connect a 1 ohm resistor with it. Now the current through the resistor will be 100 A. Now we connect a 1:2 step up transformer with the A.C supply, and then ...
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What is the equivalent resistance between A and B? [closed]
This question is from a past paper in the Advanced Level Examination of Sri Lanka. Now, I know there are lots of "find the equivalent resistance" questions out there, but I searched ...
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Calculation of equivalent parameters of a few RL links for direct current circuit [closed]
Is there a way to calculate equivalent parameters of a few RL links for direct current circuit (like on the generalized example on the image below)?
So far I've studied that known formulas for series/...
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Reason for current being same in a series circuit
Why current does not decrease after passing through a resistor?
Does the voltage decrease?
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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 ...
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Weird Potential Divider Diagram
How does the above circuit work? My textbook only has potential divider circuits such that there is only one output voltage. Such as this one.
Could we replace the arrowed line in the uppermost ...
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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 ...
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How much voltage would be required for a charge to have 1 amp of current with 0 resistance?
Voltage is the energy a charge has. If a charge has some energy it will move forwards. Resistance opposes the charge and it moves slower.
But what if resistance was exactly 0.
1--->How much voltage ...
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Resistors in high frequency
My question is this:
Can we use ordinary resistors like those we use in labs(1.2K ohm), in high frequency (like 4GHz)?
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How did we figure out what resistance was?
We were able to figure out that every material offered some resistance.
And we were also able to figure out that there is a constant between current and voltage at a specific temperate.
But how did we ...
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Does Ohm's law apply to a charge moving through empty space?
Clarification: I was playing with this idea and I thought of a scenario in which made me think Ohm's law might be incomplete. I will try to be as straightforward as possible. I am asking if the Ohm's ...
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Quantum Hall effect diverges at $B=0$
In the integer quantum Hall effect, with the applied magnetic field reduced, more and more LLs get filled and one can observe higher and higher plateaus in the Hall conductivity $\sigma_H(B)$. ...
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What is quantum mechanical explanation of resistance?
I would be very happy if I get any help with any of this questions. And I am sorry if I make any grammatical mistakes, I don't know grammar well. I guess, the problem for understanding how resistance ...
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When a circuit with three lights goes from series to combination, with one on the main loop and two on different branches, does power in branches $↓$? [closed]
I am considering a circuit with three light bulbs. When a series circuit goes to a series-parallel circuit with one light on the main loop and two on different branches, the total resistance decreases ...
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Is it possible to find $i’(0)$ and $i(0)$ by building and measuring say voltage across the $RLC$ circuit?
The RLC circuit equation is,
$$L\frac{\mathrm{d}^2i}{\mathrm{d}t^2}+R\frac{\mathrm{d}i}{\mathrm{d}t}+\frac{1}{C}i=0.$$
I want to know if it is possible to figure out $i’(0)$ and $i(0)$ through the ...
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How to know if resistors are in series? [closed]
According to Fundamentals of Electric Circuits, 6th edition, Alexander & Sadiku, p. 36
Elements are in series when they are chain-connected or connected sequentially, end to end. For example, two ...
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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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Reciprocity Theorems in Physics
So far I have come across reciprocity theorems in electrostatics (relating the potential and charge distributions; Griffiths) and fluid dynamics (relating the flow fields and boundary forces; ...
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If there is a resistor there is a potential drop because the potential energy gets converted to other forms, then how can the current remain constant?
I am pretty confused about this. If a current flows through a resistor in a series circuit, the resistor opposes the flow of charges. Therefore, the total charge flowing per unit time decreases. How ...
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Inverse relationship between salinity and conductivity?
I have a salt solution that is saturated at 40C, I measured conductivity and got 440 ms/cm.
I then increased the temp to 50C, add more salt until the solution is saturated again, and measure ...
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Why we use vector sum to calculate net potential in AC circuits?
My physics professor used vector sum to find net voltage at any instant in the following $RL$ circuit and said that it is equal to vector sum of phasor vector of potential drop across Resistor and ...
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Discharging a capacitor conceptual question
When a capacitor is discharging, why is the potential difference across it at any time $t$ equal to that of the resistor? Do the two potential difference's not have to add up to the EMF of the supply ...
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Does $P=VI$ contradict $V=IR$? [duplicate]
Imagine there's a dam generating power (P) that needs to be transported 100km away. Engineer Pedro suggests increasing the voltage to reduce current acording to P=VI, while Engineer Juan suggests ...
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How do the nodes affect the circuit?
I am tasked to simplify this circuit to one source and one resistor, which is equivalent to the original but obviously easier to solve.
My problem is the fact, that I don't know how the nodes A and B ...
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Do superconducting materials have "zero" work function?
I understand that superconductors have zero resistivity, however, I wonder if there is a relation between resistivity and the work function of a specific material so that a superconductor has zero (or ...
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Is my reasoning about $ε = iR$ correct, where $ε$ denotes induced emf, $i$ denotes induced current, and $R$ is resistance of loop [closed]
I came up with the formula, $ε = iR$, where $ε$, $i$ and $R$ denotes induced emf, induced current and resistance of loop respectively. I did the following reasoning to prove this formula, am i right?
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Rigorously showing that steady state will be reached in simple DC circuits [closed]
Consider a simple DC circuit in which we have a source of emf connected to some resistance $R$.
Now all the books I have consulted give me heuristic arguments as to why a steady state will soon be ...
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Heating Effect of Current wrt Transformers
I just learnt that we use step up transformers to reduce heating losses in overhead wires. I was given some values.
Say, the power plant is a 1 million watt rated plant.
The voltage is $400V$ at the ...
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Physics diagram to electrical schematic [closed]
I am asking this question on behalf of user furious.neutrino. I asked this question at Electrical Engineering Stack Exchange, but it has not received a reply, so I am duplicating it here. I think the ...
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How to calculate the total resistance? [closed]
So I am new to physics and I am trying to solve the total resistance of this circuit. My question is: because there is a battery in the same branch as R2 and a Capacitor in the same branch as R3, when ...
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Simple $RC$ circuits
I have a $RC$ circuit with a capacitor (capacitance$=C$) uncharged initially and resistor (resistance$=R$) in series with the battery of EMF $E$. Assume its internal resistance to be negligible.
Now ...
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(High School Level) How to calculate effective resistance on parallel circuits? [closed]
I was doing an AQA Physics Alevel (UK Syllabus) past paper and I came across this past paper question:
It asks me to 'calculate effective resistance between P and Q'. I had a few attemps in trying to ...
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If the current in a conductor doubles, how would the amount of heat evolved change? [closed]
So I came across this question in a textbook, and it says
“If the current in a conductor increases to twice the original magnitude, the amount of heat it releases per second would increase by how ...
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Physical Cause of Reactance of Inductors and Capacitors
We know that a capacitor and an inductor both offer some opposition to the flow of current through an AC circuit and their reactance is a measure of the amount of Ohmic opposition due to these circuit ...
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