Questions tagged [electric-fields]

For questions that utilize the concept of electric fields (commonly denoted by the letter E), or for questions whose answers likely involve electric fields. More specific than the [electricity] tag, as questions about the phenomenon & theory of electricity do not necessarily involve the discussion of fields.

Filter by
Sorted by
Tagged with
0
votes
1answer
12 views

Potential at the centre of two concentric shells

The potential of the inner shell is 10V and that of the outer shell is 5V. The potential at the centre is given in the book to be 10V. I know that inside the shell potential should be constant but how ...
0
votes
0answers
14 views

Force produced by an electron beam

Suppose an electron beam hits a positively charged plate, what is the force on the plate? I was thinking that the force on the plate is equal to the sum of the electric field produced by the plate at ...
-3
votes
0answers
24 views

Electric feild intensity due to charged ring [closed]

How to derive expression for electric feild intensity due to charged ring at a point not on its axis.
1
vote
1answer
25 views

Fields and Conductors

Is it correct to say that the field exiting the conductor is less than the field entering the conductor as the internal field of the conductor due to the induced charges is opposite in direction?
0
votes
1answer
24 views

If an object is enclosed within a metallic spherical shell having surface charge + q C. The object will carry charge - q C.?

I have doubt in the statement is there any link between surface charge and object enclosed within the shell. I think object in enclosed shell can have any charge +ve or -ve . Or it is due to the fact ...
0
votes
1answer
50 views

Why are Electric Fields an exact differential?

{$\vec E$ - Electric Field Vector ; $x^2$ is $x$ raised to the power $2$} When finding the Potential Difference between two points in a non uniform electric field, the equation of $\vec E $ given in ...
-4
votes
0answers
31 views

My question is under electrostastics [closed]

A 60 microcoulomb charge is at the centre of a cube of side 10cm. What is the total flux through the cube?
0
votes
2answers
52 views

Motion of charged particle in uniform magnetic field and a radially symmetric electric field

This question posted by me on MSE talks about a physics problem. This is what it was: (I hope someone can help me with this) Consider a region of 2-dimensional space with a uniform magnetic field of ...
0
votes
0answers
18 views

Amount of current moving through wire induced by electric field

Suppose we have a copper wire (length 4cm). We bring a negative electric field nearby and it applies 20 N/C at one end of the wire (we'll call this end A). The electrons in the wire are repelled by ...
0
votes
1answer
13 views

Deflection of charge towards current carrying wire [closed]

when a charge is projected in the direction opposite to a current carrying wire then how does the charge deflects ?
2
votes
3answers
301 views

Why is electric field in an insulator non zero?

I had read from several sources that electric field inside a conductor is zero. This is attributed to the fact that the electrons are loosely bound to the nuclei and they are free to rearrange ...
2
votes
1answer
45 views

Can the energy of a charged ring have some sense?

I know that the density and potential (in spherycals) of a charged ring is, respectively,: $$ \rho(\textbf{r}) = \frac{\lambda}{a} \delta(r-a)\delta(\theta-\tfrac{\pi}{2}) $$ $$ \varphi(\textbf{r})= ...
0
votes
0answers
21 views

The motion of a particle through a capacitor

I'm stuck trying to find an equation for the position of a particle travelling through a capacitor, however the capacitor gives an electric field that changes direction the further you get into the ...
0
votes
0answers
30 views

Charge a metal by applying potential

I don't understand why if we apply a potential to a metal it can attract electrons. An example of this is an electron gun, the anode is at a positive potential and its function is to attract the ...
0
votes
1answer
10 views

Induced field on a solenoid - dependance on position [closed]

Consider a cilindric solenoid of lenght L, with N spires of radius a. Calculate the induced field in a point P, in function of the angles $\theta_1 $ and $\theta_2$. The magnetic field for a solenoid ...
0
votes
0answers
24 views

Do stationary charges get attracted to a current carrying wire (due to change in electric charge density caused by length contraction)?

I've seen magnetic fields getting explained away by special relativity, for it accounts for the magnetism in the electron's reference frame as an electric field caused by a greater charge density due ...
2
votes
1answer
35 views

Why don't (or why do) current carrying wires attract a stationary charge placed at a distance?

I've learned that moving charges produce magnetic fields which in turn affect other charges in motion. After seeing explanations that point to special relativity, I am kind of confused. Can ALL ...
1
vote
1answer
28 views

Charge on conductors

In a books Concepts of Physics by HC Verma,It is written that one a conductor only one surface cannot be charged.Both the surfaces have to be charged in order for the net electric field inside the ...
0
votes
2answers
29 views

Electric field inside a coil

What happens to the Coulomb electric field produced by the electron beam moving helically? In principle it would be like considering several rings of charges, in the center of the ring the electric ...
0
votes
3answers
54 views

Black Body emission - Coupling of $E$ and $B$ field

I do not understand how a black body emits electromagnetic radiation. I assume that heating a black body creates moving charges which induce a magnetic field. But where is the $E$ field part of the ...
0
votes
2answers
67 views

Relativistic Force and Non-tangent initial velocities

Dear physics stack exchange, I was looking over the darker non-mainstream physics wing of youtube when I came across a video with a person who gave a simple experiment to prove you could accelerate ...
0
votes
0answers
17 views

Symmetry transformation of canonical coordinates of the EM field

The EM free field can be written with the Hamiltonian formalism as: $$H=\sum_\lambda\frac 1 2(P_\lambda^2+\omega^2 Q_\lambda^2)$$ In this expression $Q_\lambda$ and $P_\lambda$ are canonical variables....
2
votes
3answers
185 views

Line integral of a point charge

I am trying to teach myself Electrodynamics through self-study of Griffiths' Introduction to Electrodynamics, and I am having difficulty with a calculation that involves a line integral of a point ...
0
votes
0answers
15 views

Voltage in a coaxial cable [closed]

I can't seem to wrap my head around this problem. Determine the voltage $U$ between the wire ($\mathrm{r_1 = 4 mm}$) and the sheath ($\mathrm{r_2 = 8 mm}$) of a coaxial conductor. $\mathrm{Ep = 3.8 10^...
0
votes
0answers
13 views

Finding electric Field and potential [closed]

A non-conducting semi circular disc (as shown in figure) has a uniform surface charge density σ. The ratio of electric field to electric potential at the centre of the disc will be I tried it but am ...
1
vote
0answers
43 views

Charge in conductors [closed]

When an external electric field is applied, the electric inside a conductor field is zero. In a case, a external charge is given to the conductor, is the electric field inside a conductor field is ...
0
votes
0answers
17 views

Is the force experienced by charges in a conductor under the influence of electric field same

Consider the following situation: We have a normal cell , now a conductor is connected to both it's terminals. Do each of those mobile charges experience the same force due to electric field? If ...
0
votes
0answers
39 views

Free electron in sinusoidal electric field with phase shift [closed]

Suppose there is a free electron in electric field $E=E_{0}\sin(\omega t +\varphi$) at $t=0$. I need to calculate the maximum and the average speed of the electron. Let $x(0)=x'(0)=0$, so $m\ddot x=...
0
votes
0answers
15 views

Direction of electrical force in a Solenoid [closed]

Im having trouble understanding this task: Given a solenoid which has a magnetic field pointing into the paper (see attached image), what is the electrical force on a positive point charge inside ...
1
vote
1answer
34 views

Electric field inside a charged conductor

Why is electric field inside a charged conductor always zero? In an uncharged conductor if an electric field is applied then the charges reconfigure themselves as to have no net electric field. In a ...
0
votes
0answers
17 views

Equations with relevance to motion of a charged particle in attractive and repulsive field

I have three related questions on Rutherford scattering The first one is based on the derivation given here When momentum is conserved isn't angular velocity $\frac{d \theta}{dt}$ where $\theta$ is ...
0
votes
0answers
22 views

What causes the charges in conductor to move towards lower potential terminal of cell [duplicate]

Whenever a conductor is connected to a cell,what causes the conventional positivecharges inside it to move towards the lower potential level of cell.. My question is whether the charges experience a ...
1
vote
0answers
87 views

Is $\nabla \times \mathbf{D} = \vec{0}$ necesary to apply Gauss Law in $\mathbf{D}$?

Electrostatic scenario. My professor told me that to use Gauss Law (at least in it's integral form) to find a vector field $\mathbf{D}$, $\nabla \times \mathbf{D}$ must be $\vec{0}$. When we derived ...
-1
votes
0answers
10 views

How Electrostatic shielding works? [duplicate]

Why do we get a uniform charge distribution on outer surface of sphere irrespective of the position of charge inside the sphere?
0
votes
1answer
53 views

Electric field outside a conductor

Say there is a conducting cylinder in a uniform external field. The charges on the cylinder surface will distribute and create a surface charge density. Is there any reason the charge density would ...
1
vote
1answer
59 views

Can Electric field line form a right angle?

Can Electric field line form a right angle ? something that look like the letter L.. please be as rigorous as possible. Thanks in advance.
0
votes
1answer
36 views

Dipole oscillators question from Feynman lectures 1.28-29

I am confused by the Feynman lectures Vol1Ch28-29. In all the pictures, there is an electric dipole oscillating vertically. We're assuming the intensity is $E^2$ and that in the far r limit $E$ ...
0
votes
0answers
21 views

How do the electric field lines distribute inside a current carrying conductor?

We know that when we connect a conductor to a source of potential difference, an electric field is established inside the conductor. With the help of calculations which I show below, we can see that ...
2
votes
6answers
84 views

How is it physically possible that the electric field of some charge distributions does not attenuate with the distance?

Let's consider for instance an infinite plane sheet of charge: you know that its E-field is vertical and its Absolute value is $\sigma / 2 \epsilon _0$, which is not dependent on the observer position....
1
vote
1answer
42 views

How does electric and magnetic field interchanges in light propagation? [closed]

We know that magnetism is just a illusion created because of special relativistic effects and there is only electric field which is really there in reality. so how can we say that this imaginary ...
0
votes
1answer
24 views

Current in a generator

According to the Faraday law, voltage will be induced in the generator when the the loop will move in a magnetic field. This voltage will cause the current in the circuit. My question is Do ...
0
votes
2answers
51 views

How can a capacitor discharge if there is no field outside? [duplicate]

On RC circuit, capacitor discharges when the voltage supply is removed. But I've learned that the net electric field outside a charged capacitor is zero by gaussian surface and gauss law. I don't ...
1
vote
3answers
47 views

Electric field and current

When we provide a potential difference in a circuit it does nothing more than provide an electric field to the conductor,When an electric field is provided in a conductor the free electrons move to ...
1
vote
4answers
92 views

Why aren’t the electric and magnetic components of an EM wave complementary? [duplicate]

Every visualization of an electromagnetic wave is essentially some variation of this picture: In every one of these graphs, both the electric and magnetic components are shown as being sine waves ...
0
votes
1answer
43 views

Electromagnetic waves produced from a sinusoidal current

Say I have an oscillating sinusoidal current flowing on the z-axis (say $I_0\sin{\omega t}$), in a straight line conductor. This current produces an alternating magnetic field in the azimuthal ...
1
vote
3answers
67 views

Perpetual Motions in atoms up scaled to Tesla

If perpetual motion exists in atoms or its parts then why can it not exist with a collection of atoms? or can it? What exactly prohibits or where does the perpetual line physically stop? Can atoms be ...
2
votes
5answers
109 views

Why is $\oint_S \mathbf{E}\text d\mathbf{s}=q_{in}/\epsilon_0$ valid when finding electric field inside charged sphere(charges are inside sphere)? [duplicate]

Let $r < R$, where $r$ is the distance to a point from the center of the sphere where we want to find electric field and $R$ is the radius of the sphere. Why can we use $\oint_S \mathbf{E}\cdot\...
0
votes
1answer
26 views

Deflection of particle when moving out of Uniform Electric Field [closed]

A particle of mass m and charge -q enters a region between 2 charged plates initially moving along the x-axis with speed $v_x$ .The length of the plate is L and uniform electric field is maintained ...
0
votes
3answers
77 views

Why $\vec{E} = \frac{\sigma}{2 {\epsilon}}$ does not has a variable for distance?

Upon solving a question where I had to find the Electric Field $\vec{E}$ due to an infinitely large uniformly charged sheet of charge density ${\sigma}$ , I found that the Electric Field at a point ...
-1
votes
2answers
52 views

Why are there electric field lines outside the conductor but not inside?

The Electric field at point P (for an electric slab) is given by $E_P=\frac{\sigma}{\epsilon_0}$, however, since $E$ inside the metallic slab is zero, the electric field at point P is contributed by ...

1
2 3 4 5
50