# Questions tagged [voltage]

Voltage is the unit of measurement for electronic potential, from one point location to another.

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### Method of image charges for electric potential in a metallic disk

It is well known that the method of image charges is not always applicable, so I was wondering: is there an analytic way to calculate the electric potential for a point charge interacting with a ...
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### Computing the potential difference between two points using $\ \vec{E} \>=(xî + yĵ + zk̂)\frac{kQ}{(x^2 + y^2 + z^2)^{3/2}}$ [closed]

The potential difference between two points, A to B, is given to me as $$ΔV= -\int\limits_A^B \vec{E} \cdot d\vec{r}\ .$$ Since this is my first time seeing something like this as a first-year ...
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### How do i solve this impedance question asking voltage across the inductor? [closed]

I solved this question in the following way, but the answer isnt right, can someone tell me why was i wrong? plss this question is important for my exam tomorrow.
1 vote
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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. ...
35 views

### 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. ...
1 vote
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### How would voltage change in time in an electrolytic solution?

I'm building a teaching model and a question came up that isn't very clear to me. I would like some help. The voltage of a sphere (~5 cm in diameter) uniformly charged, in this case positively as in ...
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### Why is Power in an electric circuit equal to $VI$? [closed]

Where did this formula come from? Everyone I asked just told me to substitute values of in ohms law to derive this but no one told why is power equal to voltage * current. Part of the reason for this ...
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### Decreasing of a charge amount and its effects on a capacitor

There is an equation of charge amount on a capacitor you may know; This graph above shows the charge amount. And according to the book "Fundamentals of Electric Circuit from CK Alexander", ...
2k views

### 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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### Why is there no negative sign in the linear form calculation of voltage but there is a negative in the integral form? [closed]

The formula for voltage given $\vec{E}$ and $d$ is $$V = |\vec{E}| d.\tag{1}$$ However, the formula is also $$V = - \int \vec{E} \cdot dr. \tag{2}$$ Why does one of these formulas have a negative and ...
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### Determining if a capacitor will charge or discharge based on voltage [closed]

The question also says that the voltage of the battery is 12 V. We're supposed to determine if the capacitor is charging or discharging or neither. I'm just not sure how to use the voltages given to ...
80 views

### Why does the capacitance of a parallel plate capacitor increase on filling it with an insulating dielectric if the voltage is fixed?

In the case that the electric field $\textbf{E}_0$ is confined to the space between the plates of an isolated and charged parallel-plate capacitor, an inserted linear dielectric that fills the space ...
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### Calculating the ideality factor of a diode

I am carying out a semiconductor related experiment to calculate the ideality factor of a diode via I-V curves, here is the formula: Shockley Diode Formula I am trying to find n which is the ideality ...
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### Why doesn't voltage increase when the wire length increases; there's more work to be done?

This Q&A did not answer my question. The voltage of a circuit is the difference in each Coulombs potential energy at the negative pole, compared to the positive pole. At the negative pole, there's ...
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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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### 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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### 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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### Computing the electric field of a potential in a vacuum

I am attempting to compute electric field in a vacuum (preferably by finite volume method) near a high voltage accelerator element, as used in electron guns, analog televisions and so forth. By ...
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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 $0\Omega$ ...
1 vote
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### Mismatching Batteries of Different Voltages

Consider connecting two batteries of different voltages $x$ and $y$ in parallel. Considering a series circuit, the total voltage would be $x+y$. However what happens in this parallel case? From my ...
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### Is this a proof of a mathematical statement using physics?

In problem 3.16 of "Introduction to Electrodynamics" by D. J. Griffiths, we are told to find the potential inside a cube, 5 sides of which are at zero potential, and the remaining side (...
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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 ... 31 views

### 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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### In the formula of capacitance of a conductor the $V$ is potential of conductor once fully charged or initial potential of conductor used to charge it

capacitance $C=q/V$ The $V$ here is the final potential of the conductor which is to be charged or the initial potential of the source conductor? We are not charging it by using a battery rather ...
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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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### Some books write $V(\vec{r})$ instead of $V(r)$ as a notation for the electric potential, so which one is right? [closed]

Some books write $V(\vec{r})$ instead of $V(r)$ as a notation for the electric potential, so can the electric potential depends also on the direction?
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### I can't use $\int \frac{kdq}{\mathcal{r}}$ to calculate the electric potential of an infinite charge distribution, can I?

Since $\int \frac{ kdq }{\mathcal{r}}$ assumes infinity is the reference i can't use it to calculate the electric potential of an infinite charge distribution, right?
1 vote
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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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### Transformer primary Voltage and emf relation

This is a conceptual query. So if possible kindly answer more conceptually. Consider an ideal transformer. We have a input voltage Vp, and voltage in secondary coil as Vs. now, we write emf equations,...
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### Reference point of potential in case of a battery

When we define electric potential of a charge,we need to take a charged body as a reference and then we bring the test charge to calculate the electric potential. Now,electric potential energy is ...
1 vote
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### Does a non-grounded disc, near a charged disc, behave like one side of a parallel plate capacitor?

I’m using a new FEA software and I’m getting an unexpected result. This is a simplified diagram of my simulation problem. I expect that a disc charged with one volt would have a capacitance similar to ...
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### Does current develops instantaneously as we apply potential difference?

I had this doubt from the starting since I studied current electricity, that if we apply a potential diff. Across a resistor, does the current flow instantaneously, if it does then the communication ...
26 views

### Potential effects of magnets on a Police Taser?

I couldn't find any similar topics and was curious if anyone had thoughts on the following: Could a magnet (ceramic and/or neodymium etc.) have an adverse affect on a Police Taser, if held to the ...