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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 [tag:electricity], as questions about the phenomenon & theory of electricity do not necessarily involve the discussion of fields.

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Direction of Uniform Electrical Field [on hold]

An electron is travelling in a straight line through a vacuum with a constant speed of $1.5 × 10^7\text{ ms}^{–1}$. The electron enters a uniform electric field at point A. The electron continues to ...
35 views

Symmetry Argument of a Line Charge

I am been trying to make sense of my professor's lecture notes on where he talks about line charges; in general, I am lost when it comes to the symmetry argument in the case that $E_\phi=0$ on an ...
32 views

Magnetic fields and electric fields relation [duplicate]

Why do we treat magnetic fields to be different from electric fields?.I thought special relativity had solved this thing.
751 views

Electric field due to a hydrogen atom

Electric field due to two opposite charges According to the answers in the previous questions, if you separate the two charges from each other, they will produce a non-zero electric field ...
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Electric field due to two opposite charges

We know that The net electric field due to two equal and oppsite charges is 0. But let us consider a charge +Q in an isolated system. An electric field E will be emitted by it. Similarly, a -Q ...
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Electric potential and its signs

When we are calculating the potential due to the sphere, why do we integrate from $r$ to $\infty$ instead of from $\infty$ to $r$? Or do we integrate from $r$ to $\infty$? Regardless of who does the ...
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Why are induced field lines circular?

Whenever we have a changing magnetic flux through a conductor an induced electric field is generated. It is often said that these induced electric field lines are circular in shape.But why is this so?...
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Gauss' Law not including all of the system

Suppose we have a system of two parallel conducting plates charges $Q$ and $-Q$ and charge densities $\sigma$ and $-\sigma$. In this case, to find the electric field, Gauss' Law is used with a ...
56 views

In which situation does the electric field vary sinusoidally with position?

If I have a point charge q at the origin then the electric field will be $$\mathbf{E} = \frac{1}{4\pi\epsilon_0} \frac{q}{r^2} \hat r$$ that is to say that electric field will diminish by the square ...
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Why do the sides of the Gaussian pillbox contribute nothing to the electric field? [on hold]

It says that the top and bottom of the pillbox contribute to the $E$ field but the sides don’t. I couldn’t quite understand this, please Help.
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Why is electric field constant over the charged solid Gaussian sphere?

I saw this example at griffiths. It’s a basic question about gauss’s law but I saw the electric field being treated as a constant and thus, it got outside of the integral. I couldn’t quite understand ...
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What is the function $q$ in the definition of charge density?

Supposed we define $\lambda = \frac{dq}{dl}$. If I think of this intuitively, this makes sense; the linear charge density at a point is tiny amount of charge at that point divided by the tiny length ...
21 views

Point with 0 electric field and non-zero potential

I'm quite new to physics and I don't totally understand the concepts of potential energy and work. I've been watching MIT courses and I got pretty confused, considering the following situation: We ...
20 views

Leaked electric field in Transmission Line theory

In the previous image I can't understand why the leaked electric field in plate conductors is axial (On the same axis of propagation), And if it becomes axial then the wave in the conductor is not <...
51 views

Why is this equation correct?

This problem seems to be solved the exact same way in multiple solution books, so I'm certain that the way it is done is correct and that I'm just rusty when it comes to calculus due to multiple years ...
23 views

Is it (practically) possible to create non-uniform electrostatic in the form of a Fourier series?

Is it (practically) possible to create a non-uniform electrostatic field of the form $$E_x = \sum_{k=0}^N C_k e^{ikx}.$$ (keeping it in one dimension for simplicity) If yes, how?
56 views

Why the magnetic field is perpendicular to the electric field?

I am a high school student. Recently I have read about magnetism. Each time I found magnetic field has to be perpendicular with electric field. Is there any explanation why is it?
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Directly integrate $\mathbf{E}$ inside a spherical cavity in dielectric [closed]

P3-23 in Cheng E&M, 2nd edition: Determine the electric field intensity at the center of a small spherical cavity cur out of a large block of dielectric in which a polarization $\mathbf{P}$ ...
63 views

Can a moving current carrying wire produce electric field?

As we know, a current carrying wire can create a magnetic field which is perpendicular to the direction of current (From relativity, we can understand why magnetic fields are produced ) and the net ...
25 views

Two point charges $Q_1$ and $Q_2$, are a distance a away from each other. Where is electric field zero? [closed]

Problem: Two different point charges $Q_1$ and $Q_2$ are a distance $a$ away from each other. The point charges are both positive. Where is the electric field zero? So far, I've found the total ...
24 views

Gauss law in electrostatics

Consider a solid conductor,if the conductor makes a free electron inside that due to thermal energy ,so that causes one positive ion inside the conductor, my question is according to gauss law inside ...
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In electrostatics, $\nabla\times\mathbf E=0$. Why is this?

I can understand why this is mathematically but I do not understand the actual why, like in words why this is.
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$E$ outside a Metal Spherric Shell with a off-center Point Charge inside Shell

If a charge +Q is placed inside a metal shell (NOT at the center), as shown below. I can understand that E will be 0 between inner surface and outer surface due to this is a conductor. Then according ...
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What's the electric field in a sphere with charge $Q$ and an inverse linear/square law density of charge?

In Classical Electrodynamics by Jackson problem 1.4 asks to find the electric field as a function of the radius of a sphere charged with a charge Q and with a spherically symmetric density that goes ...
47 views

How do we arrive on the same expression for Gauss's law when deriving it for a sphere or any other figure (say a cylinder)?

For a circular surface, the surface area of the circle is cancelled by factors in the denominator of $E$, leaving behind only $Q/\epsilon_0$. But what about when we conside a cylinder? How so we ...
15 views

Is this calculator for the electric field inside of a square correct?

I made a desmos tool calculating the components of the electric field [u,v], at a point (a,b) inside of a square of continuously and uniformly distributed charge with linear charge density $c$. https:...
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What will magnitude of the net force on any of the charges be?

When identical point charges are placed at the vertices of a cube of edge length $a$, each of them experiences a net force of magnitude $F$. Now these charges are placed on the vertices of another ...
This may be very silly, but I need to understand this to get my concepts right. Consider the fact that the electric field b/w the Earth's surface and the ionosphere is on an average $100$ V/m, then ...
In electromagnetism, we say that any conservative electric field $\vec{E}(\vec{r})$ is associated to a scalar potential $V(\vec{r})$ such that $\vec{E}(\vec{r}) = -\nabla V(\vec{r})$. If the electric ...