All Questions
24
questions
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Why Does equipotential surfaces gets father apart in the regions of weak electric field?
If we consider a charge in space then we can draw infinite number of spheres (taking the distance between the spheres equal) around the charge and these spheres act as equipotential surfaces. Now, As ...
- 179
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
3
answers
761
views
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?...
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
0
votes
1
answer
79
views
Energy stored in capacitor over time
I know that the maximum energy that can be stored in a capacitor is:
$$
U = \frac{Q^2}{2\,C}\,.
$$
What I am asked is to say how much energy was stored when half of the electric charge that could be ...
- 117
-1
votes
1
answer
36
views
Does electrical energy depend upon number of charges particles [closed]
This might sound silly,but,electrons in electric current carry electrical energy,so,does electrical energy depend upon the number of electrons?like if in a area,more electrons are flowing,then there ...
- 151
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votes
4
answers
2k
views
Explanation of voltage $= dW/dq$
I recently started to learn about circuit theory, and in the book it straight up defines voltage as $ dW/dq$, or the derivative of energy with respect to charge. The thing is, I always thought of ...
- 139
2
votes
2
answers
1k
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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
-1
votes
2
answers
189
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Can negative electric potential be converted into kinetic energy?
If we were given that the potential energy $U$ at some point in space was negative, could we calculate its kinetic energy (KE)? If potential energy were positive then we could simply use the formula $$...
0
votes
1
answer
90
views
Negative charge that gains voltage in an electric field?
I read that a negative charge that gains potential in a field loses energy I know the formula that relates voltage and charge to joules. But I can't visualize it. Where are the equipotential lines? ...
- 65
1
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1
answer
443
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Is voltage just the energy created from the separation of charges?
Recently learnt some physics, and I just want to check my understanding
0
votes
4
answers
2k
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Does potential energy of a charge gradually decrease when it moves from a higher potential level to low potential level?
I have read that the analogy of gravitational field is similar to electric potential energy..now if I have a ball falling from higher potential level to lower potential level,then the potential energy ...
0
votes
3
answers
100
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If voltage represents an energy difference between two points, why don't electronic appliances all use the same amount of energy?
As I understand it, voltage is an energy difference between two points.
$$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
-1
votes
3
answers
1k
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How Work =Voltage * Charge? [closed]
We know,
Work/charge=volt
So work =volt*charge
But work =Fd
So my question is since both voltage and charge are not dependable on distance,so how come work can be calculated without factoring in ...
4
votes
5
answers
4k
views
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
0
votes
3
answers
801
views
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 ...
- 972
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
3
votes
4
answers
5k
views
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
0
votes
3
answers
2k
views
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 ...
2
votes
1
answer
109
views
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
0
votes
1
answer
335
views
Potential energy between 2 moving charges
Let's say we have 2 positive charges repelling each other along a line.
Initially they are pretty close and over time get far away from each other.
The key is that both charges are allowed to move and ...
- 301
1
vote
2
answers
904
views
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
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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