Questions tagged [short-circuits]

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Will I get a shock holding a superconductive wire?

Assume a current carrying superconductive wire is in front of me, with no voltage source attached. If I hold it, will I get a shock? Forget for a minute that the superconducting wire will be too cold ...
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3 answers
55 views

A simple question about parallel connecting a short circuit (+the physical interpretation)

1. Introduction We know that $$1/R_1 + 1/R_2 = 1/R_t \ (equation \ 1)$$ $$\therefore R_t = \frac{R_1\times R_2}{R_1+R_2} \ (equation \ 2)$$ when $R_1$ and $R_2$ are connected in parallel and $R_t$ is ...
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1 answer
30 views

What does it mean to ground in this context?

This is a homework problem that I already submitted, but am still unsure about. I am consider the following situation, re we have a conducting sphere of radius $R$ with charge $q$, which is surrounded ...
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2 votes
1 answer
69 views

Is the eigenvalue of an eigenstate the same as its (global) phase?

I'm trying to understand Shor's Algorithm by reading this Qiskit textbook. At some part the following equation comes up: \begin{equation} U |u_0\rangle = \frac{1}{\sqrt{12}} \begin{pmatrix} |3\rangle +...
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0 votes
4 answers
173 views

Why can you shortcircuit a car battery with a wrench in your hand and stay safe?

In this demonstration by Prof. Walter Lewin a car battery is shortcircuited with a wrench. The experimenter is holding the wrench in its bare hands, so why he is not experiences an electric shock? ...
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2 answers
61 views

Kirchhoff’s Voltage Law validity in short circuited circuit

Imagine a circuit with a battery and a resistor. Now I connect a resistance-less wire in parallel with the resistor. There will be a potential difference between the two ends of resistor, so current ...
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3 answers
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A problem with the path of least resistance

I have a question about short circuits that I haven't been able to solve. From this we know: The total voltage V is constant, and the total current I is inversely proportional to the total resistance ...
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2 answers
260 views

Can grounding wrist prevent electrical shock?

Today while repairing some electronics and wearing anti-static wristband like on picture below I got thinking - in theory, would it be possible to avoid shock while working on mains by grounding ...
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1 answer
31 views

Magnetic rail problem with inductor and battery (resistance less)

A metallic rod (negligible resistance) can slide frictionlessly on two parallel metallic rails separated by a distance l in the presence of a perpendicular magnetic field (B). The ends of the rails ...
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3 answers
80 views

Earthing vs grounding

In some websites they say there is a difference between Earthing and grounding but some of them say they don't.Is there any difference between "Earthing" and "grounding"?
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1 vote
1 answer
47 views

Voltage - Current Relationship (IV graphs)

This is probably a really simple question but for some reason, I'm finding it difficult to grasp at an atomic level. My physics textbook has a statement that says: "As the voltage across a ...
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1 vote
2 answers
105 views

What means "A grounded conductor has potential equal zero"?

When I have a force field $\boldsymbol{\vec{F}}$ it tells me how the momentum of the particle will change given in a position on space. When we talk about an electric field $\boldsymbol{\vec{E}} = \...
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1 vote
1 answer
57 views

How does an instantaneous current discharge occur when you connect a power strip to itself?

It is a light hearted joke that connecting a power strip to itself is a source of "infinite power". While this is obviously untrue, I always disregarded it and never really thought much of ...
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1 vote
2 answers
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Why is the potential in conducting wire of negligible resistance is same as the potential of the terminal of the battery to which it is connected?

I am a high school student and I am very confused "why is the potential in conducting wire of negligible resistance is same as the potential of the terminal of the battery to which it is ...
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0 votes
1 answer
128 views

Is drift velocity of electrons 0 in 0 resistance wire?

In a 0 resistance wire, the electric field inside the wire is 0 as there is no potential difference. That means that when charges start to flow, no external force acts on them. But it doesn't mean ...
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12 votes
5 answers
978 views

Calculating equivalent resistance [closed]

In the given circuit, find the equivalent resistance between points A and B. I solved this question in two different ways, out of which one gave the correct answer. The correct method is the most ...
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1 vote
4 answers
611 views

If there was zero potential difference between any two points in a circuit would current still flow? [duplicate]

Suppose there is a wire of zero resistance.So,by Ohms law it must have 0 potential difference between any two points across the resistor,now one connects the wire to a battery which has non-zero ...
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0 votes
1 answer
66 views

Does random motion of electrons take place in 0-resistance wire?

In nodal analysis we often assume a wire to have 0 resistance and hence we assume that its ends have the same potential. As the potential difference across the ends of the wire is 0, there is no ...
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1 vote
3 answers
254 views

Why do resistors in parallel with uncharged capacitors get eliminated from the circuit?

I was doing a problem where I was asked to find the current in an R-C circuit 'just after' the switch had been closed i.e at t = 0. All of the capacitors are initially uncharged. Could someone explain ...
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1 answer
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Graph profile of the voltage drop vs resistance across a resistor, and the physics behind electric potential difference

I am a student and I have been trying to understand the relationship between voltage drop and resistance, and the underlying physics of Kirchhoff’s voltage law. I am aware of Ohm’s law and I can ...
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1 vote
1 answer
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What are the the actual similarities between Electric Circuits and magnetic circuits

I have surfed google to find an answer to that but all I keep seeing is "differences" and not actual similarities. So what exactly do electric circuits and magnetic circuits have in common.I ...
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3 votes
2 answers
77 views

Can deadly electrocutions be prevented by wearing a simple wire?

One way to die when working with electricity is for enough current to pass through your heart, not much is needed. Often you are protected by wearing shoes or by the current flowing through two parts ...
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0 votes
3 answers
53 views

Capacitors charging, resistance much more?

I am overwhelmed by the amount of doubts i am having regarding this device (CORRECT ME WHEREVER I AM WRONG PLEASE) First things first if we connect a capacitor using two ideal wires (for each plate) ...
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0 votes
2 answers
287 views

Direction of current using superposition method

I have to calculate the current I and the voltage between a and b using the superposition theorem. I can solve this directly by calculating the voltage between points, but I have to do it with that ...
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0 votes
7 answers
138 views

Can someone explain, in clear terms (not unmathematical) what short circuit is? [closed]

I don't get the idea about what short circuit is. In a few questions I have come across, it appears to be a short circuit but the answers say otherwise. In fact, I don't have a conceptual ...
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0 votes
1 answer
73 views

Why would lamp A be shorted here in this circuit when testing the circuit with a power supply?

I'll really appreciate a response to this question, thanks for considering. Suppose I have this circuit (image from a CIE past paper question): Actual text (image here) in the problem: It is said ...
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2 answers
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DC circuit- parallel vs short circuit [duplicate]

In a DC circuit, imagine a resistance of 10 Ohms connected parallel to a resistance of 20 Ohms, which is also parallel to a battery of V volts. In such a case, current will be distributed to the two ...
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1 answer
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Short circuiting a PN semiconductor device

Consider the potential distribution across a PN junction. The difference in the Fermi levels between the differently doped semiconductors leads to a 'built-in' voltage across the semiconductor ...
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1 answer
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Why doesnt a wet circuit work

I mistakenly poured water on my the area of my TV remote which has the cell and apparently the circuit connections.A thing to ponder is that why doesnt a circuit work when it becomes wet , despite it ...
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0 votes
2 answers
68 views

Root mean square current

An electric bulb is designed to operate at 12 volts DC. If this bulb is connected to an AC source and gives same brightness , what would be the peak voltage of the source? To this question answer is ...
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-3 votes
2 answers
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Can u explain the line, " A voltage source likes open circuit load and hates short circuit load."

Can u explain the line, " A voltage source likes open circuit load and hates short circuit load." In my textbook it just says 'for obvious reasons'
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0 votes
2 answers
207 views

Ohm's Law gives me different values compared to the practical experiment with a multimeter - can you explain why?

I am studying physics in high school and am trying to understand electronics. Using Ohms law I calculated VIRP values for a simple circuit with three 1000 ohm resistors and a 9V battery. I then set up ...
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0 votes
1 answer
137 views

Kirchhoff's voltage law for an ideal circuit containing only a capacitor

Let's say I have an ideal open circuit (i.e. there's no resistance in the conductors) containing only a charged capacitor and then I close it. Now, the charge on one end of the capacitor will move to ...
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2 votes
2 answers
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Parallel connected wire with no resistance

i am having a problem digesting this circuit. This wire seems wierd and i do not understand how the current flows through this circuit. if we suppose all of them resistors have the same resistance and ...
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1 answer
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Voltage over current source and its short circuit wire

I am still trying to understand the meaning of an ideal current source. To this end, I drew this abstract circuit above. Let's say the current source is ideal, and the voltage symbols you see ...
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1 vote
3 answers
123 views

Short circuit analysis (theoretical)

I believe this question has been asked $>666$ times already, however I am trying to analyse it from a different perspective. Consider the completely theoretical case of an ideal voltage source ($0 ...
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11 votes
12 answers
5k views

Why doesn't Kirchhoff's Law work when a battery is shorted with an ideal wire?

Kirchhoff's law states that the sum of voltages around any closed loop sum to zero. The law is true as the electric field is conservative in circuits. Why can we not apply the law here? Why doesn't ...
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0 votes
1 answer
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What's the source of voltage? [duplicate]

I've been told that in a DC circuit with a battery the negative terminal of the battery "pushes" electrons in nearby atom away of it and those by themselves cause electrons in other atoms to move, but ...
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-1 votes
3 answers
91 views

Is there a non-zero field within an ideal current carrying wire?

Its true that there is a non zero field (in fact,a field of the magnitude of counter electric field inside the battery used) within a current carrying IDEAL wire (unlike static condition). Thus there ...
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-2 votes
1 answer
160 views

Why do I get a short circuit if I connect the red wire? [closed]

Why the red wire generete a short-circuited with $I_2=0$ and $\Delta V_2=0$? I have three loops and if I apply the 2nd Kirchhoff's rule, I will have $$\sum_{\color{red}{\text{2nd loop}}} \Delta V=0$...
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0 votes
1 answer
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Why do we leave out this 20 ohm resistor when tabulating the Thevenin resistance? Is it because of short circuit? [closed]

I bumped into this particular question. I approached the question in the wrong way. I took into consideration of the extra 20 ohm resistor. but the answer key doesn't seem to consider that. Is it ...
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2 votes
0 answers
615 views

Why does this magnetic charger cause short circuit when it sticks to the metal leg of my table? [closed]

Recently, I have bought this product. It is basically a USB cable, with a magnetic end, and a tiny attachment that goes into the mobile device. I plugged it into my laptop cooling stand (which has ...
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2 votes
2 answers
533 views

How could an ideal conductor with 0 resistance conduct electricity? [duplicate]

A very simple circuit consist of a resistor, a battery, and some conducting wires connecting the resistor to the battery(assuming resistance of the conducting wire is $0$). It is always assumed that ...
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0 votes
1 answer
56 views

Why is the information of a time delay missing in formulae of voltage drop across elements when we emulate DC with an AC voltage supply?

In an AC circuit, the reactance of capacitive and inductive elements are determined by the frequency of the AC signal. When we try to emulate DC analysis by putting $\omega$ = 0 , the capacitive ...
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1 vote
3 answers
243 views

Would we need a battery if there was no resistance?

I'm struggling to wrap my head around this idea. Imagine that we have a wire with no resistance ($R=0$). According to Ohm's law $V=IR$, the voltage drop ($V$) between any two points would be 0, and ...
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5 votes
5 answers
2k views

Resistors parallel to short circuit

I have a trouble solving this problem. (Actually, each resistor is not parallel with the bottom wire since the voltage across each of them is different with that of wire.) In the manual, the bottom ...
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2 answers
51 views

What will happen if an ideal current source is connected to a isolated resistance?

I know that ideal current source is a theoretical thing. But when it comes to solve problems we have to consider these scenarios. Now suppose an ideal current source is connected with an isolated ...
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1 vote
2 answers
3k views

How does current flow in a short circuit? [duplicate]

In a short circuit, the potential difference across the terminals of a battery (consider a single cell with internal resistance)is 0 according to the equation $$V=E-Ir,$$ where $r$ is internal ...
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1 vote
2 answers
1k views

The importance and the role of a switch in an electrical circuit

There is this simple test: Three identical bulbs are connected in the circuit illustrated in the figure. When switch $S$ is closed: a] The brightness of $A$ and $B$ remains the same, while $C$ goes ...
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0 votes
1 answer
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On ground wave propagation

My textbook says, (ground wave propagation) "Horizontal component of electric field in contact with the earth is short circuited" I am not understanding, what do you mean by short circuited electric ...
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