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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How can this circuit be simplified in the first moments after the circuit breaker closes?

The book states that in this circuit after the transient the branch with the capacitor can be ignored while the branch with the inductance can be considered constituted only by a resistance. This ...
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Is there a contradiction at the top of this circuit?

Applying kirchhoff's second law to the first loop, the current in the upper branch remains determined and is $2.4$ A to the right (if $i$ is to the right then $-10i + 24 = 0$). Then the current in the ...
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Ammeter readings of variable resistor

Question The diagram in question has no numerical values. $R_1$ is a resistor of constant resistance. $R_2$ is a variable resistor set to minimal resistance. $V$ is an ideal voltmeter. $A_1$ & $...
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Instantaneous current and average current

Imagine a simple electrical circuit with a battery and resistor. We know that the average current in any part of this circuit remains same . My question is : is the instantaneous current also same ...
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Why is lamp D off?

I understand the other lamps, but the answer for lamp d is that it is off as no current flows through it. I don't understand why? Please help.
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EMF being equal through KVL

In the given figure,we connect three cells of different emf which are $V_1,V_2,V_3$ with a resistance $R$ in the first loop. Now suppose we emit current $I$ from $V_1$. $I$ gets divided into $I_1$ and ...
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What will be the equivalent resistance of the circuit? [closed]

I am getting different answers 2 ohm when I used symmetric cutting method and 4/3 ohm when I used junction method
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Diode in infinite circuit [closed]

This is an infinitely long circuit where the main voltage source is $V$ and other sources are $V_1,V_2\cdots$ where $V_n=n^2V_1$ for $n \ge 1$. All the diodes are ideal which means their resistance is ...
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Quantum nonlinear resonator/ transmon qubit

The transmon qubit -quantum non-linear resonator- has 4 elements in the electrical circuit. (Here is the circuit) starting at the 21:00 mark. We have R, L, C,Cd and Voltage. I already know which L,C,...
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How is there current if there's no voltage?

Hi, I was trying to solve this problem, it asks to find the reading of ammeter. I think it has no resistance here. Does it mean that there's no potential difference, no voltage across ammeter? But how ...
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How to understand the model of electric current and potential in circuits?

According to what I have learnt, there is always a potential difference across a resistor in a circuit (having a battery). Considering a simple 'resistor' circuit, when we apply an e.m.f in the ...
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If one of the parallels of a parallel combination of resistors is broken, how will it affect the other parallels?

All these bulbs have equal resistance and the equivalent current is 6A. I want to know what will happen if bulb 3 is fused. All the sources I have came across say that the bulb 1 and bulb 2 will glow ...
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How to calculate the total resistance of this complex circuit? [duplicate]

how do I calculate the resistance of the following complex circuit?
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What is the difference between antenna input impedance and its radiation resistance?

I got to know that the input impedance of the halfwave dipole antenna is given as: $Z_{in}$=1/$I_m$* sin($\beta$(H-|Z|)) where $I_m$ is the maximum current on the antenna( when excited with a 1 volt ...
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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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Current flowing from lower to higher potential

In the above circuit, two cells are connected in series to an external resistance $R$. Now the current going from point $A$ must return back to point $B$ of the cell. But for that it has to pass ...
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The Resistance in an electric kettle [closed]

I have an electric kettle with two parallel heating elements, both with resistance $R_0=2\,\Omega $. Both can be independently shut on and off. There is also another resistor with resistance $R$. Upon ...
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Why isnt the angle between EMF and LC impedance 90 degrees in AC circuit?

I have a generic LC circuit where the inductor and capacitor are in series and we have alternating EMF. I'm trying to find the the impedance of the circuit with phasors. A phasor diagram shows ...
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Voltmeter reading in a bridge circuit

Why would it be wrong to calculate the voltmeter reading in the following diagram as one plus 2 ohms is 2/3 ohms as they are in parallel, hence the p.d. reading on the voltmeter must be the current ...
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Exercise with full wave bridge rectifier [migrated]

I study an example of youtube video https://www.youtube.com/watch?v=Kl8IOESVWlM an i want to make transfer function vo = f(vi) when i use the piecewise linear diode model. I worked with the following ...
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Relation between conductance and capacitance?

Say I have a material like activated carbon VS copper. Activated carbon has a surface area of 500 meters^2 per gram. Copper is a lot more conductive and with copper powder at .3-.5 microns I’ve seen ...
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Why is the wave impedance calculated as $\eta = \eta_0 / \sqrt{\epsilon_r} = \dfrac{377}{\sqrt{4.0}} = 188.5 \ \Omega$?

I am currently studying the textbook Microwave Engineering, fourth edition, by David Pozar. Chapter 1.4 THE WAVE EQUATION AND BASIC PLANE WAVE SOLUTIONS says the following: Plane Waves in a Lossless ...
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$V$-$I$ characteristics and circuits [closed]

The only solution stuck in my head goes through finding the resistance from the slope of the curves and using it somehow in the solution, however, I can't figure out what voltage do I use for X and Y? ...
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Confusion about electrical potential difference

I am confused why voltage is same across parallel circuit as shown above where wire is an ideal conductor. The voltage at top part of the resistor $R_1$ and $R_2$ is same. $R_1$ has higher resistance ...
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Is this argument about sharp and blunt lightning rod right?

Actually I came to know that sharp lightning rods are not sensitive to the weak electric field comparing to blunt lightning rods. Resistance will resist the formation of field on the rod. So, we know ...
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Voltage and series circuit [duplicate]

Suppose I have 2 series circuit. One will have resistance $R_1$ and the other $R_2$. Now my question is why is voltage difference same across both resistor? The top part of both resistors should have ...
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1 answer
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If loads are perfectly balanced, and line resistances are zero, is ground wire redundant?

Here is my understanding of neutral and ground: The return current through the neutral wire is the vector sum of three phase power. If loads are perfectly balanced, the vector sum is zero, and the ...
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What happens to the electric field lines in a high resistance conductor?

When a conductor is connected to a potential difference, an electric field occurs inside the conductor. We know in a high resistance conductor (for example a 20m long thin carbon rod connected to a 1....
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2 answers
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Does the resistance of a conductor depend on how the current flows through it?

For example if we take a cylinder with inner radius $a$ and outer radius $b$ would its resistance for the following three situations be the same? (a) current flowing from inner face to outer face (b) ...
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1 answer
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Do multiple current flows exists in a conductor? Does a slower current provide extra resistance?

If you have a running marathon with lots of people the slower people are in a sense an obstacle for the faster people behind them. The slower people create extra resistance. Is there an analogous ...
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1 answer
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Question regarding power consumption by a device running on electricity

Say I have a device with resistance $R_2$, connected through a wire of resistance $R_1$ to a source providing potential difference $V$. If I close the circuit then current $I$ will flow through, and ...
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How does 'symmetry' of a circuit allow us to find currents when a junction splits into 2 different resistors?

The book says what the picture shows. There's no parallel or series resistors and I could solve it with 4 different currents (if the top blue arrow is i3 and bottom green is i4) but that's a 4 ...
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1 answer
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What is the resultant EMF when two cells of different EMFs are joined in parallel?

when cells of same emf are joined in parallel then the resultant emf is taken to be the emf of the cells but what if the emfs are different??
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Power equation in railgun operation?

In a capacitor discharge through a plain resistor, the capacitor power supplied at any instant is VI; the power dissipated in the resistor is I²R. So VI = I²R. Consider a railgun operated with a ...
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Mathematics of the star-mesh transformation

I'm trying to understand the star-mesh transform from a mathematical perspective. This transformation removes a node and by definition, the topology of the network changes, but the resulting network ...
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Circuit with internal resistance [closed]

A circuit is formed by connecting a resistor between the terminals of a battery of electromotive force (emf) 6 V. The battery has internal resistance. Which statement is correct when 1 C of charge ...
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Measure a unknown battery? [closed]

I have a physics exercise that goes: Given resistances $\mathrm{R_1 = 5 \Omega}$ , $\mathrm{R_2 = 11\Omega}$ and corresponding currents $\mathrm{I_1 = 0,5A}$ and $\mathrm{I_2=0,25A}$ connected with a ...
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1 answer
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Why is voltage drop same in parallel?

I have checked a lot of answers here but none gives a satisfying answer to the question. Doesn't different resistor dissipate different amount of energy in terms of heat? Now you might answer it's ...
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1 answer
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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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3 votes
1 answer
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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 ...
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1 vote
2 answers
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Why is electric field zero in a wire with 0 resistance given nonzero voltage?

Why is electric field zero in a wire with 0 resistance given nonzero voltage and infinite charge inside a battery? It is true that for a wire with $0$ resistance there will uniform voltage across the ...
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1 vote
1 answer
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Voltage and current through 2 resistors on circuit [closed]

Given the circuit below, with a dc supply of 25V and the resistors as are, I am asked to find the Voltage on the ends of $3.3 \Omega$ resistor and the current through the $25 \Omega$ resistor. I need ...
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Are these resistors parallel?

I am wondering whether, when analyzing this circuit, $R2$ and $R3$ can be treated as being in parallel and combined into an equivalent resistor. My issue is that it seems to me that they are parallel ...
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4 answers
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Do you "lose" electricity when you course it through subpar conductors?

Imagine I had a basic circuit - say the classic 9V battery on one end, a couple of wires, and a little light bulb on the other. Of course, in a real world example those wires would probably be ...
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1 answer
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Why are Kirchhoff's circuit laws and the nodal analysis equivalent?

Two Kirchhoff's circuit laws: Law I: at each node the algebraic sum of the currents is zero Law II: the sum of directed voltages across any loop is zero When performing the nodal analysis, we use only ...
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How does putting a resistor change potential difference between two points?

Suppose that we have a closed circuit that consists of a single wire. If we said that the wire has resistance $R_1$, then the electrons would travel through the wire and the potential difference ...
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2 answers
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CGS of resistance

What's the CGS unit of resistance? Is it the same as that in SI system, i.e. ohm (Ω)? I googled but found no explicit answer.
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1 answer
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Voltage drop across a circuit misunderstanding

Consider a circuit with a 20 volt battery and a resistor (no other components). Next, let's say I choose a point A on the positive terminal of the battery. The current flows from point A, around the ...
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1 vote
2 answers
57 views

Quality factor of LCR circuit

If we are given a parallel or series LCR circuit, we know the quality factor of these circuits ( which we can see in many books). But if we are given a LCR circuit with the three components connected ...
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4 answers
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Resistance of Electric Bulb Filament and Electric Heater coil

While solving a numerical, I learnt this data: take resistance of bulb filament as $1200 \Omega$ and resistance of electric heater coil as $100 \Omega$. My question is if both bulb and heater are ...
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