The electric-field tag has no wiki summary.
0
votes
1answer
34 views
The potentiality of the electric field
Could you, please, explain me using just words why electric the field is potentially? I know the proof using integral: $A = \int_{12}q\overrightarrow{E}\overrightarrow{dr} = ...
2
votes
1answer
66 views
Difference between electromagnetic radiation (EMR) and Electromagnetic Field?
I'm a freshly graduated electrical engineer. One course that I really struggled with was Field Theory, because it was a lovely assortment of vector calculus and things that were explained to me well ...
0
votes
0answers
64 views
The electric field inside a uniformly polarized cylinder
Given a uniformly polarized cylinder with some polarization $P\vec{z}$ which has radius $R \gg d$ where $d$ is the height and $R$ is the radius. The cylinder's center is on $\vec{z}$ and it's on the ...
5
votes
3answers
100 views
Horizontal $E$-field for a charged conducting disk
For part of a simulation I am writing, I need to know the electric field emitted from a charged conducting disk. If the disk was laid out in the $x$-$y$ plane, I am interested in the field in that ...
0
votes
0answers
36 views
Work required to pull capacitor plates apart when connected to battery [closed]
For (a), I just use $F = k \frac{Q_1 Q_2}{r^2}$, then (b) $W = - \Delta U = - qE \Delta d$, correct so far? But how do I do (c)?
0
votes
0answers
30 views
Energy content after moving point charge [closed]
I have the following exercise:
In point A there is a charge with $Q_1 = 3.3\times10^{-5} C$
In point B charge $Q_2 = 8.5\times10^{-6} C$
In point C charge $Q_3 = -6\times10^{-6} C$
This happens ...
1
vote
1answer
51 views
Maximum separation when 2 unlike charges shot apart
I want to compute the maximum separation when 2 unlike charges are shot apart from each other
...
0
votes
2answers
83 views
Difference between electrostatic and magnetic field [closed]
In this, F (the force set by the field) is perpendicular to the speed of the particle. In which case does F change the absolute value of V? Why or why not?
1
vote
1answer
40 views
Why electric field outside the sphere that carries polarization is 0?
There is a sphere with radius $R$ that carries a polarization
$$\vec P(\vec{r})=k\vec r$$
$\vec r$ is the vector from the center.
I found electric field the outside generated by the sphere is $\vec ...
1
vote
2answers
221 views
Does a current carrying wire produce electric field outside?
In the modern texts of electromagnetism in the presence of stationary currents the electric field is assumed conservative $\nabla \times E =0 $. Using this we get $E_{||}^{out}=E_{||}^{in}$ which ...
0
votes
0answers
35 views
Spherical charge in two different dielectric materials
I am trying to freshen up my memory about electrical fields and I came across this exercise from school.
A sphere with a constantly distributed charge is located in between two different dielectrics ...
0
votes
1answer
89 views
Electric field around charged cylinder
This is a homework question, so please don't give me the answer outright. I just need help conceptually.
"A cylindrical shell of length 190 m and radius 4 cm carries a uniform surface charge density ...
1
vote
0answers
37 views
Static electrical attraction [closed]
Coulomb's law is used to calculate the electrical attraction between 2 charged particles, what formula do I use to calculate an electrical attraction magnitude between 2 plates? Let's assume the first ...
0
votes
1answer
31 views
Gaussian surface in a charged infinite plance sheet
The following question arises on the use of Gauss law. In the charged finite sheet problem, we consider a Gaussian surface on only one side of the sheet. But, In the case of an infinite sheet, we ...
0
votes
1answer
50 views
Electric field and potential [closed]
An oil drop of radius 0.70mm containing a charge of -4.8 x 10-19 C is placed in an electric field if the drop remain stationary at the point find the magnitude and direction of electric field ...
1
vote
2answers
133 views
Energy of particle in electric field
I'm taking a physics class and the professor teaches us really basic things in lecture and then gives homework way beyond what he taught in lecture. Obviously I need to find some resource other than ...
0
votes
1answer
104 views
Does the electric field inside a sphere change if point charge isn't in center?
As i understood , if you have a point charge in the center of a hollow conducting sphere then the electric field inside it, is zero because the charge distribution is spherically symmetric.
But ...
0
votes
1answer
220 views
Non conducting charged planes
I have two parallel non conducting charged planes with opposite charges $6\mu C/m^2$, area $A = 3m^2$ and distance between the planes $d = 0.004 m$. I know the potential between these two planes is ...
1
vote
2answers
97 views
Electric vs. Gravitational shielding [duplicate]
There are great similarities between electric and gravitational fields and, furthermore, a room can be electrically shielded so that there are no electric fields simply by surrounding it with a ...
-1
votes
1answer
227 views
What's the electric field with a point charge not in the center of the sphere? [closed]
That's a hollow conducting sphere link
My charge is at P (10uC). R = 0.15m. PS = 0.05m. DS = 0.35m. What's the electric field at point D?
3
votes
2answers
100 views
Estimation of the internal electric field strength in the pn-junction
I would like to compare my result in an order of magnitude. So, How can I estimate the strength of the electric field in a typical Si PN-junction?
0
votes
1answer
55 views
Possible to generate an electromagnetic field from moving an object through a magnetic field?
Is it possible to generate an electromagnetic field from a stationary rare earth magnet with a hole in it by passing an object through the hole?
By definition, a Lorentz Force is the force on a ...
0
votes
1answer
71 views
Electric field of a negative charge
Displacing something against the gravitational field, gains it potential energy. Moving something against the nature requires work. If the electric field of a negative source charge 'Q' points inward, ...
2
votes
2answers
203 views
Electric field of a negative charge
How was it discovered that the electric field of a negative charge points towards the charge itself? Is it true?
(Courtesy of wikipedia)
0
votes
0answers
18 views
Electric field outside nonconducting sphere [duplicate]
An electric charge $Q$ is distributed through out a nonconducting sphere of radius $r_ 0$ and has a spherical cavity of radius $r_1$ centered at the sphere's centre. Assume the charge $Q$ is ...
0
votes
1answer
51 views
Why do fields decrease with distance? [duplicate]
For example, electric, gravitational field decreases with $1/r^2$. Is it like decrease of energy of an object when goes it is moving with friction/air drag etc?
Does it mean that field's strength is ...
0
votes
1answer
198 views
Electric field due to nonconducting sphere
For calculating electric field outside a nonconducting sphere with a hollow spherical cavity. When I use the rule (Charge density= $dQ/dV$), I don't know exactly what is $dV$, is the volume here ...
1
vote
1answer
70 views
Should the electric potential of a positively charged sphere be negative?
Because the indefinite integral of the electric field results in a negative value? (As the function is proportional to $r^{-2}$?
I've got to be missing something... Help please!! Thanks!
Also, I ...
1
vote
0answers
27 views
Microscopic fields inside a conductor
In a neutral conductor if we assume electrons as point charges, the electric field in the space between them cannot be identically zero. This microscopic field may be very weak. What if we were very ...
0
votes
0answers
35 views
Charges and Fields [closed]
Three charged particles lie along the x axis of a Cartesian coordinate system. q1 is located at x = 0,
q2 lies at x and q3 lies at x = r. All three charges are positive, but only q2 is free to move. ...
3
votes
2answers
153 views
Influence of charged particle's own electric field on itself
I read this in my textbook: A charged particle or object is not affected by its own electric field.
Since I find this completely unintuitive and my mind is yelling "wrong! wrong! how could a particle ...
3
votes
1answer
146 views
What do physical properties of materials trigger the capacitive touch screen?
I have watched some youtube videos about capacitive touch screen
http://www.youtube.com/watch?v=ZHzaVzYEZbw
http://www.youtube.com/watch?v=GmCE18RMEeQ
The videos show that a conductor(finger), in ...
1
vote
1answer
226 views
Electric field strength between 2 positive charges [closed]
I'm having a lot of trouble trying to solve this problem:
Three identical point charges of magnitude $+1.0$ $mC$ are located at the corners of a square that is $1.0$ $m$ on a side. A point charge of ...
2
votes
1answer
450 views
Gradient of the electric potential
I was wondering if for a point-like charged object, does the gradient of the electric potential point in the direction of maximum increase or maximum decrease of the function $V$?
1
vote
2answers
133 views
Electric lines of force
Why cant electric lines of force pass through the charged sphere? Well, basically that's how a Faraday cage works, but how can it be so?
4
votes
2answers
198 views
How does lightning “know” where to go?
If lightning comes down in, say, a large flat field with a lightning rod sticking out of the middle, the lightning will strike the rod.
How does it "know" the rod is there?
Will it always strike the ...
2
votes
3answers
119 views
Explanation on the resulting forces of two positive point charges
Why will the resulting force lines of two positive point charges be like this:
I would expect this:
1
vote
1answer
101 views
Electric Field inside a hollow ball, excentred of a homogeneous charged ball
Q:
We have a homogeneous charged ball with radius R which contains a ball-shaped hollow (with radius := r and distance from center of the bigger ball (M) to the center of the hollow (N) := b).
...
1
vote
3answers
184 views
Why can we use Gauss' law to compute electric field?
For simplicity I'm considering only the sphere case.
In the Gauss' Law formulation we have some field E introduced by charges $Q$ inside some sphere, then we compute flux and integrate, and we get ...
3
votes
1answer
160 views
Electric field caused by magnetic field
Does electric field caused by time varying magnetic field form closed loops(electric field starts from a positive charge and ends at a negative charge)? and are they conservative or non-conservative ...
0
votes
0answers
65 views
Electric field singularity
What's a general proof for the log-singularity of electric field near the edge of a uniformly charged surface?
1
vote
1answer
122 views
Finding the Electric Field (and other information, besides)
The problem I am working on is:
Two parallel plates having charges of equal magnitude but opposite sign are separated by 29.0 cm. Each plate has a surface charge density of 33.0 nC/m2. A proton is ...
2
votes
2answers
133 views
Electric field lines
If electric field lines cannot terminate in empty space, in the simple example of two equal charges what happens to the line starting from one of the charges toward the other in the middle?
2
votes
2answers
266 views
Higher To Lower Electric Potential
The question I am working on is:
"An electron moving parallel to the x axis has an initial speed of $4.65 \cdot 10^6~m/s$ at the origin. Its speed is reduced to $1.27 \cdot 10^5 ~m/s$ at the point ...
0
votes
1answer
144 views
Finding the electric field
The charge per unit length on a long, straight filament is -91.9 µC/m.
(a) Find the electric field 10.0 cm from the filament, where distances are measured perpendicular to the length of the ...
0
votes
0answers
101 views
Having a hard time answering this electric field question [closed]
What is the electric field at a point when the force on a 1.45uC charge placed at that point is F=(3.0i-3.9j) * 10 ^-3N? Need to find a and B. Sorry I am new to this and do not know how to use the ...
0
votes
1answer
51 views
Help for density of charges in electric field [closed]
This is for a homework assignment so it would be great to have a hint or an explanation of how to do it. In a certain region in space, the electric field is given by
$\vec{E}(r) = \dfrac{A}{r} ...
1
vote
1answer
57 views
Charged plane in an electric field acceleration
A perpendicular plane to an electric field's lines of force has more electric flux than a plane that is in parallel with the lines of force, right?
Does this mean that a charged plate would ...
2
votes
1answer
147 views
Minimizing potential energy of a dipole in an electric field
My test paper asked me which way a dipole should be orientated in an electric field to minimize its potential energy. My answer was that the dipole should lie parallel to the electric field with the ...
0
votes
1answer
187 views
Electric Fields
The problem I am working on is, "In the figure below, determine the point (other than infinity) at which the electric field is zero. (Let $q_1 = -2.45\ \mu C$ and $q_2 = 6.5\ \mu C$)
Here is a little ...
