All Questions
129
questions
1
vote
2
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429
views
Calculating the electric field produced by a line on a point
Here's the question:
The electric field of a point charge can be obtained from Coulomb's law, But since here we have the charge distributed continuously over some region, the sum becomes an integral:
...
- 13
1
vote
1
answer
200
views
Ampere's Law Confusion [closed]
I had this question recently in a test. Different methods are yielding different answers. Can someone point out the mistake?
We are given 4 infinite wires carrying current out of the plane as shown. ...
- 736
-1
votes
1
answer
1k
views
Electric field at the center of a square
Let be a square composed by a wire uniformely charged, the electric field at its center should be zero because the contribution of every infinitesimal element of the wire is compensated by its ...
- 145
0
votes
1
answer
87
views
What is the physical role of field lines in electrostatic induction?
In explanations of electrostatic induction of a conductor $B$ by the charge on another conductor $A$, there is often reference to the field lines.
For example, in a capacitor the electrostatic ...
- 2,617
3
votes
1
answer
442
views
Theorem for which polarization in a dielectric ellipsoid inside a uniform electric field is constant
I read on textbook that there is a theorem for which, given a dielectric ellipsoid in a external uniform electric field $\bf{E}$, under special conditions on the orientation of $\bf{E}$ with respect ...
- 2,617
7
votes
5
answers
1k
views
Hollow conductor containing charge: why is internal field cancelled outside and why are the field oustide the cavity zero inside the cavity?
I've a doubt on the following situation. Consider a hollow conductor $A$ (of arbitrary shape) containing another conductor $B$ (again of arbitrary shape), with a positive charge $+q$.
By the ...
- 2,617
0
votes
1
answer
472
views
How does the electric potential change on the inner conductor when the outer conductor is grounded? [closed]
The conductors are spherical (thin) shells, the inner one is off-center from the outer one. Both initially charged and neither grounded. Charge $Q_a$ at $r=a$ and $Q_b$ at $r=b$. The space between the ...
1
vote
2
answers
9k
views
Work: Moving point charge from center of conducting shell to infinity
Consider a point charge $q$ placed at the center of a neutral spherical conducting shell extending from radius $a$ to $b$. What is the work needed to move the charge out to infinity?
The simple ...
- 659
1
vote
1
answer
2k
views
Can't seem to derive the formula for the electric field over a square sheet
I'm trying to derive the formula for the electric field a height $h$ above the center of a uniformly charged square sheet with sides $2a$.
To do so I'm using the formula for the electric field above ...
- 343
-1
votes
1
answer
69
views
Work required to bring particle towards grounded plane
I have a quick question:
If you suspend a charge $q$ above a grounded conducting plane a distance $z$ above the plane, you get that the charge induces a negative surface charge on the conductor. The ...
- 1,023
4
votes
1
answer
6k
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Harmonic motion of negative charge between two positive ones [closed]
I have to prove that a negative charge will execute an harmonic motion when placed in the line that separates two positive charges $Q$. (The negative charge $-q$ will not be placed on the center).
I ...
- 501
3
votes
2
answers
9k
views
Find the electric field of a uniformly polarized sphere
The problem statement, all variables and given/known data
We want to calculate the field of a uniformly polarized sphere of radius=R
Relevant equations
$$V(\vec{r}) = \frac{1}{4 \pi\epsilon_{0}} \...
-1
votes
2
answers
491
views
How to compute work needed to build a configuration of charges
Suppose an alignment of four charges in the vertices of a square. The first pair on one diagonal has positive charge and the other negative charge, all charges are of the same absolute value. length ...
0
votes
2
answers
92
views
Electric field of uniformly charged plane
Which are the null components (in a Cartesian coordinate system) of the Electric field of uniformly charged plane in $x=0$?
I consider the coordinates : $(x,y,z)$
I think that $E_x = 0$, $E_y \ne 0$, ...
- 11
0
votes
2
answers
2k
views
Calculating charge density $\rho(r)$ using Gauss law (both forms)
Below is a question given in my assignment. I tried applying Gauss law in both forms, differential and surface integral form. But both there is a difference by a factor of $2$. Is the differential ...
- 639