All Questions
34
questions
0
votes
2
answers
67
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Voltage: work to move a charge, or difference of electric potential?
Let's say I have a single positive charge inside of an electrostatic field. I want to move this charge from point A to point B and determine the voltage between the two points.
Points A and B are the ...
- 3
0
votes
3
answers
169
views
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 ...
- 9
2
votes
5
answers
611
views
Can we use work equation to derive Ohm's law?
Ohm's law states:
$$\textbf V=\textbf I\cdot\text R$$
where $\textbf V$ is voltage, the electric potential difference from a point to another (Electric potential is the potential energy of a positive ...
- 219
1
vote
2
answers
117
views
Working of battery in circuit
The battery has a potential difference. So, shouldn't battery generate an electric field directing from the positive side to the negative side? If that's the case, we know that potential in a wire(...
- 1,179
0
votes
3
answers
512
views
What is the correct derivation of energy stored in parallel plates capacitor?
I am little confuse in deriving the energy stored in the capacitor. I read two different derivation in totally different way but yet getting the same value.
Here they have calculated work done by ...
- 121
2
votes
1
answer
2k
views
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
9
votes
10
answers
6k
views
Why is Power = Voltage $\times$ Current?
So P = I*V because V is the amount of energy per coulomb and I is the amount of electrons going past a cross sectional area in one second.
So if we do the math, since V = J/C and I = C/sec, if we ...
- 191
2
votes
2
answers
516
views
What is the meaning of external work in electric potential?
We learned that $$-Work = \Delta U = q(Va-Vb).$$ However, we write that $$W = q(Va-Vb)$$ in this question. Why don't we write the minus sign in the equation? How does external work affect the minus ...
- 23
0
votes
1
answer
32
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How do we know that a battery has 5 voltage?
Since Voltage = work done per coulomb and in a battery we don't know how much coulomb exists (or is it known because I read somewhere that we are unaware) and for the work done I assume we can find it ...
-1
votes
1
answer
236
views
Decrease of potential by negative charge
Initially there is a body $A$. To increase it's potential we give positive charge to it which means we need to do more work to bring a test charge from infinity. Now we bring a negatively charged body ...
- 1,179
0
votes
1
answer
3k
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Derivation of the electric potential inside a non-conducting sphere
Assuming that the electric field at a distance $r$ from the center of a non-conducting sphere with radius $R$ and uniformly distributed charge $Q$ is $E=\frac{1}{4\pi\epsilon_0}\frac{Q}{R^3}r$, we are ...
- 33
1
vote
0
answers
22
views
Can work be positive when looking at a negative charge experiencing a voltage? [closed]
Using V=W/q when q is negative and V is positive do we write the work as negative? In my question it says “How much work is done in moving 6 electrons through a potential difference of 2V?” My answer ...
- 43
-1
votes
1
answer
241
views
How is the work done along an equipotential line zero?
If a charge is brought from some distance to a point which lies on the equatorial line of an electric dipole, the work done is 0 and so is the electric potential. But how should I imagine this?
- 817
3
votes
2
answers
194
views
Deriving $-\vec{\nabla}V$ from $V_b-V_a=-\int\vec{E}\cdot d\vec{l}$
I'm trying to understand how to derive $-\vec{\nabla}V$ from $V_b-V_a=-\int\vec{E}\cdot d\vec{l}$. I'm not really familiar with the gradient operator, I know how to compute it and I know that $\vec{\...
- 299
1
vote
2
answers
371
views
How can an electric field do work? What does the work in this case?
I'm studying electromagnetism and I'm a little confused on what this textbook says:
The highlighted part is what makes me confused. First thing, "The difference in potential energy is equal to ...
- 299