# All Questions

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38 views

### What really is an electric/magnetic field?

Have you ever wondered how we can see this field or how it's formed its shape in space? I know we can feel that there's one by its effect which is the force. But what does it look like? We all know ...
44 views

### How can a spring contract when magnetic field cannot do work?

When a spring is kept in a magnetic field and current is passed through it, its edges act as parallel conductors and due to the action of Lorentz force, they pull themselves together. A spring ...
34 views

### Visualization of electromagnetic waves with potentials?

I wonder if there is out there any visualization of the propagation of electromagnetic waves, not only with the electric and magnetic fields components but an actual visualization of the underlying ...
56 views

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### How electric field and magnetic field propagate through vacuum where there's no charge present? [duplicate]

As we know light travels as an electromagnetic wave...but electric fields and magnetic fields are interactions between charges...they are the forces acting on stationary and moving charges ...
29 views

### Electric field due to changing uniform magnetic field

I think this could be a misunderstanding on my part , still I want to clarify this.Suppose in a region of boundless expanse, there is a uniform magnetic field which changes at a rate $\frac{d\phi}{dt}$...
73 views

### EM-Wave: Calculate magnetic field $H$ from electric field $E$

In an exercise I am supposed to calculate the magnetic field from the electric field for a plane, harmonic wave in vacuum. $$\vec{E} = - E_0 \cdot \sin(\omega t - k z) \cdot \vec{e_y}$$ Using the law ...
33 views

### What do you see when you are inside a transparent conducting material?

Lets say that there exists a transparent conducting material. Lets carve a cavity in the meat of the conductor big enough for a person to stay in. There exists an external electric field. But, We ...
121 views

### Electromagnetic waves according to Maxwell

If a variable Electric field creates a variable magnetic field and VICE VERSA (according to Maxwell's equations), then why don't we enter a loop where E vector and B vector keep creating one another ...
16 views

### Guided propagation in transmission lines

Can you help me on understanding why we may say this transmission line the propagation is guided and there is not any radiation? It is a 2-conductors transmission line, in which the conductors are ...
41 views

### Is the flow of charges in inductor though electric field zero?

How electric field inside the wire of an inductor is zero (i.e. material of which loop is made — note material is assumed to be a superconductor), then how electrons flow in an inductor if electric ...
85 views

### Complex vectors: Electric and Magnetic Fields

I have a doubt about the physical meaning of the complex representation of electric and magnetic fields. Let's consider an electromagnetic wave, in which both electric and magnetic fields propagate ...
20 views

### Velocity Selector Question with Unknown Voltage

In a diagram, electrons are emitted from a hot coil with initial velocity 0 at plate A and then pass through a uniform field between two plates (A and B) where $V=1.00\times10^4$ volts. After, they ...
58 views

### The electric and magnetic field, reaching to infinity

I have difficulty’s to accept that the electric and magnetic field components of photons as well as of electrons and the other subatomic particles are extended to infinity. For practical use that does ...
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### Derivation of $B$ field and $E$ field

For an infinite plate of charge, the E field is (density of charge per area) divided by (2*vacuum permittivity). In deriving it, we used Gauss' Law and say that the flux through the two ends of the ...
40 views

### Is the electric field from light independent from the light magnetic field?

I was reading about antennas and I found an statement somewhat like this "loop antennas are more efficient compared to other antennas when close to the human body since the human body interacts more ...
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### Helical motion of a charge in magnetic and electric field

Suppose there is a positive charge undergoing circular motion in the x-y plane because of a magnetic field acting in the negative z direction. If a uniform electric field is switched on in the same ...
57 views

### Counter Torque in Electric Generator

I am going to use some sort of “dynamo” or electric generator component to generate electricity from the flowing drilling fluid. However, the effect of the magnet rotating within an electrical coil ...
55 views

### What electric and magnetic field lines look like in some examples?

I have seen this but couldn't understand so I wrote my own question. We all have learnt in school that electric field lines never intersect. Same is the case for magnetic field lines. But I have a ...
125 views

### Does Electromagnetic wave propagation really use $E$ to create $B$

I was studying how electromagnetic waves (EM waves) were generated and propagated. I was shown a dipole antenna with an AC source sloshing charges back and forth. To my understanding, when the ...
41 views

### why doesn't EM waves get weaker as we travel further away from the source [duplicate]

I know that as we get further away from the charge or from the magnetic field source both magnetic field and electric field decreases ,so why don't electromagnetic waves get weaker as the travel ...
103 views

### Why do we assume simply connected domains and continuously differentiable fields in electromagnetism theory?

In many textbooks, including Griffiths', they erroneously claim that a field is irrotational if and only if it is conservative (there exists a scalar potential). This is true only if the domain of ...
143 views

### Why can't a particle that carries magnetic charge exist? [duplicate]

Electron is the source of electric field and changing electric field produce magnetic force, what about particle that can do vice versa? My concern is how come universe favors particles that carry ...
115 views

### Is there is any way to prove the Faraday's law of induction?

I want to know if there is any way to prove the Faraday's law or is it just an experimental observed phenomena? More specifically, is there any reason why the proportionality constant is 1? How did ...
124 views

### Proof that true passive linear memristors don't exist

This is a sequel to the following (now irrelevent) question: My attempt to implement linear memristor Assume the "conceptual symmetry" of the fundamental passive circuit elements holds: Then let's ...
462 views

### Are Kirchhoff's Laws violated in case of varying magnetic field?

I was watching a video of Walter Lewin (8.02x-Lecture 16 to be precise), where he demonstrates an experiment which violates the Kirchhoff's Law. The way I interpret Kirchhoff's laws is by ...
48 views

### What actual difference does it make whether electric or magnetic field lines are open or closed?

If both electric and magnetic fields attenuate with distance by the inverse square law, what difference does it make that the latter's field lines are 'closed'? And if a magnetically-induced electric ...
73 views

### How does a time varying magnetic field induce an electric field?

I've been trying really hard to understand this phenomena. Just exactly what happens in the region of space swarmed by this changing magnetic field that creates non electrostatic electric fields, ...
83 views

### Should loop choice affect induced electric field?

Let's say we have a time varying magnetic field, but that it is uniform over a region, for instance $B(x,y)=(t+2)\hat{z}$ for $x,y,z\in[-5,5]$. Since we have a changing magnetic field, there will be ...
45 views

### Particle accelerator adapted to transport humans

Would it be possible to create a human transport system that uses the same principles as a particle accelerator? So if you had a vacuum tube that could fit a 2 m diameter metallic sphere/pod that ...
54 views

### Do Electromagnetic waves exert equal force on positive and negative charges?

Waves in the Electromagnetic fields propagate with the speed of light and have perpendicular E- and B-components. These components should exert a Lorentz force on a charged particle that exists in the ...
608 views

### How can I detect an electric field?

I can easily detect the presence of magnetic field over a surface by using compass or by placing some iron filings. But how could we similarly detect electric field over a place?