All Questions
24
questions
4
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5
answers
4k
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Why is voltage described as potential energy per charge?
Voltage is often called an electromotive force since it causes a flow of charge. However, it is described in terms of Joules per Coulomb or Potential Energy per Charge.
Question: How does the ...
- 497
3
votes
4
answers
5k
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When should I use $U=QV$ as opposed to $U=\frac{QV}2$?
In my electricity course, I am having trouble understanding the difference in between $U=QV$ and $U=\frac{QV}2$ when talking about energy stored in a system.
My idea was that when the potential is ...
- 309
2
votes
2
answers
1k
views
Static electricity: High voltage but low energy
I watched a video of a serie called "The mechanical universe" recorded at California institute of technology in which was said that
"A Van der Graaff generator with a voltage of near ...
- 131
2
votes
1
answer
2k
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Energy of a Continuous Charge Distribution
I had a question regarding the derivation for the following expression of the energy of a continuous charge distribution
$$W=\frac{\epsilon_0}{2}\int_\text{all space} E^2d\tau$$
To get this result, we ...
- 129
2
votes
1
answer
109
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what is difference between region around a charge and region out of it?
Basically I want to know what makes a region around a charge particle so affective that another charge will have energy when brought in this region or it will experience a force when enters into this ...
- 309
1
vote
2
answers
1k
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Energy of a capacitor
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capeng2.html#c3
So I have some doubts in this:
The energy stored on a capacitor can be expressed in terms of the work done by the battery.
How ...
user184272
1
vote
1
answer
70
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Why was $U=\frac{1}{2}QV$ not listed in my book as the potential energy of a capacitor?
$$U=\frac{Q^2}{2C}\tag{1}$$
$$U=\frac{1}{2}CV^2\tag{2}$$
$$U=\frac{1}{2}QV\tag{3}$$
$(1)$ and $(2)$ were listed in my book. However, I think $(3)$ is also a valid formula. Is there any particular ...
- 1,018
1
vote
1
answer
443
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Is voltage just the energy created from the separation of charges?
Recently learnt some physics, and I just want to check my understanding
1
vote
3
answers
761
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Why do we use a unit positive charge while calculating the electric potential? Can't we use unit negative charge?
Electric potential is the amount of Work required to move a unit positive charge from infinity to a region of an electric field. Why do we need a positive charge for that? Can't we use negative charge?...
1
vote
2
answers
904
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Understanding parallel plate capacitors [closed]
I need help with understanding this assignment. I originally though of using the equation of Eo*A/D = Q/ΔV but I don't know how to answer this without actual numbers to plug in besides the epsilon-not ...
user106292
1
vote
1
answer
123
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Capacitance question
A capacitors capacitance, C is equal to Q/V right?
If Q was somehow cut in half, would the potential difference also be cut in half, since V is directly proportional to Q?
And if so, Its C would be ...
- 13
0
votes
3
answers
2k
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Is voltage just energy per electron?
I know that voltage is just a difference in electrical pressure, but if voltage doesn't increase the velocity, or charge of electrons, then it must just increase their energy, right? How else would an ...
0
votes
3
answers
100
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If voltage represents an energy difference between two points, why don't electronic appliances all use the same amount of energy?
As I understand it, voltage is an energy difference between two points.
$$V_f - V_i = - \int \mathbf{E} \cdot d\mathbf{s}$$
But consider a toaster and a refrigerator each using their own 120V ...
- 4,131
0
votes
1
answer
12k
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Electron volt and Voltage
Voltage is the work done per unit charge. Given by:
V = W/q
Electron volt is the maximum kinetic energy gained by the electron in falling through a potential difference of 1 volt. Given by:
K.E (...
- 1,159
0
votes
3
answers
801
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Problem with the calculation of the energy stored in a capacitor
I was looking at the calculation of the energy stored in the capacitor, and I don't see why the calculations make sense. It goes as follows: the potential difference and charge on a capacitor satisfy ...
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