4
votes
Dipoles as vectors
Rotational dynamics. The governing equation of the rotational dynamics of a system w.r.t. to its center of mass reads
$$\frac{d \boldsymbol{\Gamma}_G}{dt} = \mathbf{M}_G^{ext} \ .$$
Considering only ...
- 10.7k
3
votes
Why electric field increase near the cable connected in AC 220V socket even current is zero?
The electric field depends on the potential difference (voltage) between the wires in the cable, not on the current going through the wires. The electric field will be strongest inside the cable, ...
- 36.1k
3
votes
Accepted
Does cutting out the surfaces with no surface charge affect the charge distribution on the remaining parts of a conducting surface of arbitrary shape?
Removing the uncharged parts of a charge distribution would not change the field configuration elsewhere. To show this, start with the Poisson equation (assuming the permittivity $\epsilon_0$ is the ...
- 936
2
votes
What is the net macroscopic electric field at any point inside a dielectric?
You are both right, as @basics points out. Any external electrostatic field is produced by a charge density somewhere in space. Whether you want to divide that in to two parts ($E_{ext} + E_{out}$) as ...
- 1,786
2
votes
Accepted
Electric force is zero in a solenoid
If you do account for resistance then there will be charge accumulated on the windings to create the $E$-field associated with the (presumably small) voltage drop between the terminals, like in this ...
- 4,912
2
votes
Electric force is zero in a solenoid
I'll do the one dimension wire (which can be coiled or not). The length is parameterized by $x$, a Cartesian coordinate.
As stated, it has a current:
$$ j(x) = j_0 $$
and that means there is an ...
- 35.4k
2
votes
Accepted
Does the geometric shape of the cross-section of an infinitesimally thin conducting charged thread (wire) affect its electric field?
I assume the charge is uniformly distributed around the major radius for all these tori.
You are right. Shape and conductivity make smaller and smaller differences as a torus approaches a thin ring.
...
- 41.1k
1
vote
Accepted
Electric field experienced by a charge
What we measure (with a load cell for example) is the force on charge 2. And we can test that $F \propto \frac{Q_1Q_2}{r^2}$.
Then we define the electric field in the location where $Q_2$ are as: $E = ...
- 16.7k
1
vote
Electric field at a point due to dielectric inserted in between a parallel plate capacitor
The induced charges on the dielectric will attract the charges on the plates. Since the dielectric is inserted partially between the two plates, the charge on the plate near the dielectric will ...
- 513
1
vote
Electric field at a point due to dielectric inserted in between a parallel plate capacitor
Consider the situation before the dielectric was introduced (left diagram) and after the dielectric was introduced (right diagram).
There are two possible scenarios.
The first is when the capacitor ...
- 97.9k
1
vote
How will the capacitance of a capacitor reduce when the distance between the plates is increased?
Now I know that if the potential difference between the plates increase that capacitance will reduce
Ideally, this is not the case. Capacitance depends on the geometry of the conductors, not the ...
- 57.2k
1
vote
Comparing Electric Potential Energy of two Charges
In the case that A and B both have the same positive charge: remember that potential energy associated with a position (it is not defined as something that requires two positions e.g. A and A') is the ...
- 1,492
1
vote
$z$-component of electric field due to a static square loop
The electric field at a point P located at a distance $z$ above the center of a square, due to only one side of the loop is given by,
\begin{equation}
\mathbf{E}(P)=\frac{\lambda}{4\pi\epsilon_0}\int_{...
- 184
1
vote
What is the net macroscopic electric field at any point inside a dielectric?
What is producing the component you're defining as $\vec{E}_{ext}$? Here Griffiths is dealing with electrostatics and, for what we know, namely Gauss' law for the electric field $\nabla \cdot \mathbf{...
- 10.7k
1
vote
Electric Field Within a Conductor
Let's split the answer here, first treating the link between the micro- and macroscopic description of the physics, then showing that there is no current and no electric field in a conductor using a ...
- 10.7k
Only top scored, non community-wiki answers of a minimum length are eligible