All Questions
Tagged with electricity voltage
396 questions
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What is steady state current?
I am currently trying to understand the following paper:
On the nonlinear electromagnetic coupling between a coil and an
oscillating magnet
http://iopscience....
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In a transformer why do we consider the lost voltage to resistance negligible?
In my text book it says:
"The induced emf in the primary coil opposes the pd applied to the primary coil,$V_p$. Assuming the resistance of the primary coil is negligible, so all the applied pd acts ...
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Since voltage determines an electron's energy, why is it current rather than voltage that is harmful? [duplicate]
Electrons have more energy with higher voltage so it seems that voltage would be what actually determines how harmful it is, because it would have more energy to lose.
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What physically determines what voltage something has? [closed]
I know that voltage is energy per charge / energy per electron, but since something such as a wall outlet has 120V with a lot of current but a mostly harmless low current Van De Graff generator has ...
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How does RPM and the Number of Coils affect a Generator output?
I’m making a simulation where the user inputs a value of force to apply to turn the generator. This is used to calculate torque and then rpm.
The user can also decide how many coils the generator ...
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318
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Is 220 V, 50 A equally dangerous for a person as 1A, 11000 V? [duplicate]
The question is self-explanatory. I'm a high school student so feel free to use scientific terms.
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Is the speed at which electrons move through a conducting wire binary?
If a voltage differential causes electrons to move through a conducting wire, and no other forces are acting against them, will they always move at the highest possible speed through that material?
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How to measure a static electric field?
I looked up google but didn't find any design for measuring electric field that doesn't vary with time.
My own idea is to use two parallel plates (like a capacitor but without the dielectric). In an ...
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Why does this lightbulb glow faintly when I thouch it with my hand though it's not connected to the AC-source?
Take a look at these three pictures I made of one of our lightbulbs:
The lightbulb is placed in a fitting which can be put directly in the power socket. In the first picture the bulb is turned loose, ...
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Why is current slowed down by resistance?
Let's say I wire the negative pole of a battery to the positive pole. Obviously, the battery will short circuit as the electron pool in the negative side will become attracted to the positive side and ...
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What's happening when $V = I$ ($R$ equals one)?
If a circuit has a resistance of 1 ohm, and the potential difference = current, are the charges flowing at the same rate as they are losing potential energy or something? If yes, what does that mean? ...
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Why does a DC voltmeter show a zero reading when an AC voltage is applied?
One of my books says that if an AC voltage is applied across a DC voltmeter, its reading will be zero.
I think that since average value of AC voltage(in a complete cycle) is zero, DC voltmeter ...
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Are the high voltages used in transmission lines responsible for 'arcing'. [closed]
I am just generally confused at the mechanism behind electrical arcing.
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548
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Electric power and resistance dependance
According to the equations,
$$P=VI =I^2R\,\text{ and voltage } V=IR$$
it seems clear that when the resistance is lower by fixing the voltage at constant, the current is therefore, higher, generating ...
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How is energy used in a circuit?
I understand the concept of voltage and why electrons flow and my guess is their potential gradually decreases as they get closer to the cathode until it reaches 0. However, the energy in a circuit is ...
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Why does a fuse blow when connecting to opposite terminals
A fuse "blows" if current greater than fuse's rating flows through. But recently I was connecting battery terminals opposite on a motorbike; this kept blowing the fuse. When I correctly connected the ...
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What makes fruits conduct electricity?
I'm sure most people are aware of the fact that certain fruits and vegetables are capable of generating electricity. But my main question is:
1. What are the names of such fruits that conduct ...
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Why do we use a specific point to find the resistance of a non-ohmic conductor? Why not tangent?
I was wondering why can't the tangent be used to do this calculation? Can a randomly chosen point be used?
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Is potential difference the same across each branch in a parallel circuit under ALL circumstances?
If you place a cell with negligible internal resistance and an EMF of 5V in parallel with 2 resistors, as shown below, each resistor will have a potential difference of 5V across it.
However, if you ...
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Reduction of energy losses in transmission of electric power
We increase voltage by using step up transformer so that current reduces and voltage increases and consequently energy losses (generally heat) are reduced.
$$E=I^2 Rt$$
But energy is also given as:
...
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Why does a resistor decrease the current flowing in a circuit if this is what current is?
This is what I know, please tell me if I am wrong:
An electron has an elementary charge (let’s call that charge e). A current is defined as the amount of e (elementary charge) that flows past a point ...
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Why don't we consider the electrical potential being converted into kinetic energy when working with circuits?
Assume we are working with a postive test charge :
In an electrochemical cell work is done by the chemical reactions to move a positive test charge from the negative terminal to the positive ...
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Why is the potential difference across a component not constant? [duplicate]
In the diagram above, the resistor has a constant resistance R.
We know that:
$$R=\frac{V}{I}$$
$$V\propto I$$
If the current increases, that means the rate of flow of charge (i.e. the speed at ...
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experiencing vibration when in contact with my desk computer and a rubbing a friend's arm [closed]
I was with a friend sitting next to my desk computer, I put my hand on the computer and the other one on my friend who is in contact with the floor. The thing is that when I rub my hand on his arm we ...
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What happens when a voltmeter is connected across two parallel circuits?
Edit: Link to question.
I'm looking at question 4.6. I cannot understand how to make sense of this arrangement of voltmeter, let alone answer the question. Any help is very much appreciated.
Are you ...
user86425
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Would an object with a high positive charge attract an object with a low positive charge?
I know that all charged objects attract neutral objects, but, for example, would an object with half of its electrons removed attract an object with one or two electrons removed?
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How powerful of an electric current would I need to fully ionize plasma under the specific circumstances below?
in a cylinder shaped vacuum chamber 4 inches in height and 5 in diameter at 1/100th atmosphere, with 3 cathodes at the face arranged in a equilateral triangle in exactly between the center and and the ...
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Among current and voltage which is responsible for brightness of a bulb?
In a circuit that is fitted with a bulb, which is the factor that affects brightness of that bulb: current in the circuit or the voltage offered by the battery in that circuit?
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How do I keep the peak voltage in a coil connected to a signal generator constant, given that I'm changing the frequency?
I want to vary the frequency of the A.C supply, and hence change the peak current in the circuit. But V=IR, so won't the peak voltage also be changed if I change the peak current?
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Can someone answer my questions on the concept of voltage?
What I understand by voltage in a circuit is that an electric field causes electrons to move from the negative terminal to the positive terminal. As it does so it converts its electrical potential ...
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Voltage of Arcing electricity
In Star Wars, Count Dooku electrocutes both Anakin and Yoda at a distance of about 5m. Obviously this is not meant to be scientifically accurate as it is a fictional movie, but how much voltage would ...
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What creates the high voltage in Van de Graff generator
I tried to in detail, explain what creates the high voltage in a Van de Graff generator. But I got problem doing that.
Van de Graaff generator:
First some background of a Van de Graaff generator, ...
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Why is this a circuit in parallel if it is topologically different than a parallel circuit
I'm struggling to understand why the left circuit is equivalent to a parallel circuit. I'm trying every deformation in my mind I can think of but I can't seem to get out the second circuit.
Secondly,...
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What happens if an electrical current has two paths of unequal length?
Suppose I connect one 1 km cable and one 1000 km cable to the same pole of a power source and also connect them together at the other end. Suppose (theoretically) the longer cable has the exact same ...
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Current across two points in space and zero electric field
I was wondering what would happen in the following case:
There's an electric field and points A and B nearby the field. As you can see, the's no electric field at those points. Will there be a ...
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Why would 4 batteries in a device not drain equally? [closed]
I noticed a motion sensor light was weak so I assumed the batteries were dying and removed them. To make sure I was right, I tested the 4 D alkaline batteries. One was completely dead. One was on the ...
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Can conductor be charged?
I have a copper conductor. For a while, I apply a voltage of $12kV$ DC from a source. After removing the source, will the conductor stay charged from the source if is not earthed? Will it discharge ...
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Why is work done against the electric field to move charges to charge a capacitor?
I'm a bit confused as to why there is work done against the electric field when charging a capacitor, as charge is moving from high potential to low potential.
For the sake of this question, I'll ...
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Is it safe to apply Kirchhoff's voltage law to a closed loop containing an inductance with unsteady current?
Is it safe to apply Kirchhoff's voltage law to a closed loop containing an inductance with unsteady current? If I have a circuit that is just a battery in series with a resistor and an inductor, can I ...
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Voltage difference vs number of electrons [duplicate]
When we say a battery has voltage difference, can we deduce the difference in the number of electrons at the two terminals? What does it mean to say there exists a voltage difference?
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What is meant by difference in electric potential?
I know this question like this has been asked many times but I am still so confused about the concept of electric potential and voltage etc… Like I know what voltage and electric potential energy is ...
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Can voltage be measured manually?
I am a novice in the subject of electricity so please bear with me if my questions seem naive. What I basically wanted to know is that what is voltage in its essence and whether it can be measured ...
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Potential difference between A.C. circuit
I the following A.C circuit . I could not understand why the V$_{AB}$ does not depend on non zero value of R$_0$.
According to me it should depend on it . As it will decide the amount of current in ...
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Does voltage depend on distance?
I just wanted to know if voltage increases or decrease as u move charges away from each other. My understanding of voltage is very basic. From what i know, I see voltage/electric potential as ...
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Batteries in series vs parallel
As fa as I understand it, two identicle batteries in parallel will give double the amperage than just one battery and two batteries in series will give double the voltage. If my understanding is ...
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Bulbs and brightness [closed]
This may seem like a really basic question, but why do some bulbs glow brighter than others. Is it the increased power rating?
Also I don't understand whether increasing the current or increasing the ...
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I thought I understood voltage drop in DC circuits until this [closed]
I drew a sketch. I hope it helps. Assume pigtail is disconnected from socket, as are the wires to the lamps. My voltage drop is occurring "upriver" of where I expect it. I figured on $12\,\mathrm{V}...
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Why does no current flow in a smartphone charger when it's plugged into a socket, but no phone is connected?
According to the fact that a phone charger consists of a transfomer and a recitifier, there should - still - be a difference in potentials, even though no phone is attached to the charger.
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Why can a Faraday pail not be cumulatively charged from a battery?
First consider a commonly performed Faraday ice pail experiment and my question will naturally follow:
If a charged object is allowed to touch the inside of a Faraday Pail, the charge will be ...
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How can voltmeter still measure potential difference if it has very large resistance?
I am just confused how can a voltmeter which has a very large resistance and hence small current or in ideal condition zero current still measure potential different because as far as I know voltmeter ...
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