Field Definition and 1000 Threads

The electromagnetic field can carry waves, some of them are light, others are used in radio broadcast. These oscillatory waves are distinguished by their frequency. The usual pickup that we get from electric currents in the circuits in the walls of the building has a frequency of about 100...

I had been studying this topic from various textbooks and review articles and I am confused about some terminologies and concepts. The question I have typed in this PDF. [Mentor Note -- Added screenshot of PDF contents]

I have broken the ring into a top arc and a bottom arc. First, let's assume an imaginary charge of +1 C is placed at point P. We will determine the force on this unit charge from top and bottom arcs. The charges in the top arc will result in electric fields that will all cancel each other...

Good afternoon to everybody. I have may be a stupid question according to the tangential part of the electric field near the surface of the conductor. Why is it zero? The normal part is zero on the distance of Debye cause of screening. But is this situation the same for horizontal direction...

Phlogiston lead to the discovery of oxygen but was later on proven to be imaginary. Can the same be said of the quite strange Higgs field and Higgs mechanism following from the strange Mexican hat potential? Is that potential just imaginary? It lead to the discovery of the eponimous particle...

Phi = int of (3xi^ + 4j^).vector dA = 3 int of(xdA) Now we put x= 3 and we get at last 36 N m^2/C. I am getting confused why E is a fuction of x. How can that be? How can we represent the E and position x on the same coordinate system. Is it right ? Because we know distance is inversely...

For a case of electrostatic field (B is equal zero), how should the force acting on a moving charge be calculated if we want to take into account all the relativistic effects? Also would it be correct to calculate the acceleration of the charge as a=F/m, or should some other formula be used? For...

I'm trying to understand Killing fields and I've hit a bump right away. Suppose I'm in a plane and using the Cartesian coordinate system, and I consider the swirly vector field \vec{v}=(-y,x) . It is easy to show that \nabla _{y} v^x + \nabla_{x} v^y = -1+1=0 . But if I convert this to polar...

When I look at the relevant equations, then there is no mention of field for a point on the surface of the shell, so it gets confusing. On the other hand, I feel the radial E will get stronger as we approach the surface of shell and magnitude of E will approach infinity.

I have been trying to calculate the magnetic flux thought a single loop of wire occurring from a magnet (meaning it has a nonuniform field), so I have the following equation: Φ=∮BdAcosθ Now my problem is that I do not know how to calculate the magnetic field strength (B)of that magnet (which...

There are actually several questions. The formula for calculating the "beam angle" of light (emitted from lights bulbs, flashlights etc) is - α = 2 arcCos ( 1 - Lm ÷ ( 2 π Cd )) Where, α = beam angle in degrees Lm = luminous flux (Lumens) Cd = luminous intensity (Candela) The above formula...

Hello, I would like to know what is the magnetic field of a half toroid. Would we use Ampere's law? So, considering that the integral is equal to BA, we would have BA = μo * i, then B = (μo * i) / r. But, using Biot-Savart's law, by symmetry, it seems that the vector sum of all the...

I'm looking for complete and detailed references on constrained Hamiltonian systems and Dirac brackets. While my main interest is electrodynamics, I would prefer a complete exposition of the theory from the ground up. So far, my knowledge about the topic comes from books in QFT, like Weinberg...

I tried as first step to find Z_q the renormalization parameter, to do so I did the same procedure to find the renormalization parameter of the gauge field of the gluon A^a_\mu when a is representation index a \in {1,2,...,N^2-1} such that A^{a{(R)}}_{\mu}=\frac{1}{\sqrt{Z_A}}A^{a}_{\mu}...

Hello! First off, for a), I am not too sure how to picture a radial field around a 3d object. I know that this spherical metal dome is basically a enlarged version of an atom, but since with problems on radial field around an atom, I don't have to consider its diameter, I'm not sure how the...

For a uniform field like this, I imagine the two plates that creates it are made of multiple atoms with charges, which are points sources that create radial fields. We know that radial fields don't have parallel fields lines, so how are parallel fields lines form when the field is made of...

When I read things about magnetism on internet, I don't understand at all about one thing: If a moving particle receive a force if it's in a magnetic field, so it should accelerate, so what happen if we change the referential so that the particle now don't move? The particle shouldn't receive...

While in QFT we remove infinite energy problem with renormalization procedure, asking e.g. "what is mean energy density in given distance from charged particle", electric filed alone would say $$\rho \propto |E|^2 \propto 1/r^4 $$ But such energy density would integrate to infinity due to...

The only explanation that I have seen in textbooks is that since the outer spherical shell is symmetrical relative to internal charged spherical shell so field every where on the outer shell is same in magnitude at every point on it. I can understand that electric field needs to be...

I have figured out how the force is towards left in the first case. I think it is due to the larger force on - charge. Please help me out with the second and third case.

I think Flux density is flux/Volume. Or is it flux/ Area Please be kind to help

Isn‘t this a straightforward problem of conservation of momentum? See attached.

A small fragment of rock found lying in a field in Gloucestershire in the UK may not have looked like much to the casual passerby ... I'm curious how this was found, if not by a "casual passerby". Did there happen to be a meteorite expert wandering in the Gloucestershire field?

Eg a gravitational field exists around a mass (A), and no doubt influences any other local mass (B) - but.. - does that field also exert an influence on the original mass (A) ? ie a sort of radial force outwards ?

Could someone explain the green highlight to me, please?

And if a star is severely stretched by tidal force, how does that affect its magnetic field and the process of it collapsing at the start of a supernova?

I could solve a similar (rather, a specific case of the above) where the current entered through a corner and left from the corner opposite to it along the body diagonal of the cube. For this specific case, I was able to easily exploit symmetry to deduce the answer (0). However, I cannot think...

k(q_1-q_2)/(R^2+x^2)^3/2

Could anyone suggest a simple video showing the Maxwell-Boltzmann distribution under the influence of a gravitational field? I trying to show a flat earther idiot how pressure gradients arise in a simple manner. Thank you all. DF

In NMR, protons that are near each other exchange energy with each other by photon emission and absorption. Proton A is spin down, and proton B is spin up. proton A emits a photon and becomes spin up, and proton B absorbs this photon and becomes spin down. have the two protons been entangled?

A wavefront is defined as a surface in space where the argument of the cosine has a constant value. So I set the argument of the cosine to an arbitrary constant s. ## k(\hat{u} \cdot r - c t) + \phi = s ## The positional information is is in r, so I rearrange the equation to be ## \hat{u}...

Interesting thing, the undergraduate courses of electromagnetism states the electromagnetic field caused by electric charge: d∗F=4π/c∗J, and students, in my opinion, mistakenly imagine the electromagnetic field as a product of charged particle. In my opinion, it is more correct to say that...

Hello, I asked a question about superconductors in 2020 and I was now wondering what superconducting chemical/material can have the highest magnetic field strength before the superconductivity is destroyed by it? Secondly, What the is maximum magnetic field strength of said material in Tesla per...

I am thinking about how an electric field has energy associated with it. If a single electron exists alone in a remote vaccuum, I believe it has it's own electric field surrounding it, and that this field has an energy content associated with it. My question is; does this electric field store...

Solution attempt

What is the relationship between the electromagnetic field and space-time? I am basically assuming that space-time is one big gravitational field. Is there a relationship between space-time and the field (I presume) created by the strong force (however negligible it may be at any significant...

Given the equation ##\frac{xy} 3##. It is a fact that the gradient vector function is always perpendicular to the contour graph of the origional function. However it is not so evident in the plot above. Any thought will be appreciated.

In Sydney Coleman Lectures on Quantum field Theory (p48), he finds : $$D\mathcal{L} = e^{\mu} \partial _{\mu} \mathcal{L}$$ My calulation, with ##\phi## my field and the variation of the field under space time tranlation ##D\phi = e^{\mu} \frac{\partial \phi}{\partial x^{\mu}}## ...

I need to find the magnetic field of a permanently magnetized cylidner: In calculating the magnetic field, i find that it should be $M_{0} \mu / 2$ and $H = M_{0} / 2$ inside. I just want to make sure that i understand the concepts in this type of problems. Since $M = H \chi (1)$, does this...

First I wrote in ##S'##, by using Gauss theorem $$ \int_{\Sigma} \underline E' \cdot \hat n d\Sigma = \frac Q {\varepsilon_0} \rightarrow E'(r)2\pi rH=\frac{\lambda'H}{\varepsilon_0} $$ $$ \underline E'(\underline r)=\frac{\lambda'}{2\pi\varepsilon_0r}\hat r $$ Its components are...

I got (a) but have no idea about b. Potential fields aren't just additive all the time are they?

I need to calculate the magnetic field generated by a static sphere at its center. On the surface of the sphere flows a constant current ##K \hat \phi##. Now, my guess was that the field produced would be equal to the field produced by a lot of rings, that is, i will split the sphere in a lot...

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When a charged particle moves in a magnetic field, the magnetic field will not work. But when a nail flying over a permanent magnet is attracted by the magnet, the magnet does work on the nail. Can anybody explain why this is so?

From what I understand, electrons are negatively charged, however, I have recently come to learn that electrons also have a spin which creates a magnetic field around each electron. I don't understand how the electron can be a negative monopole, yet have a completely independent magnetic field...

This is not a homework problem, I want to calculate the equation of the magnetic field intensity from the 3 phase currents separated by 120Degrees. The 3 currents are ##I_{{aa}^{'}} = I_M\sin \omega t ; -> eq1 \ I_{{bb}^{'}} = I_M\sin(\omega t - 120); -> eq2\ I_{{cc}^{'}} = I_M\sin(\omega t...

I can calculate the fields generated by the cylinder and the wire but I don't know how to calculate their vector sum to evaluate it at point A. Cylinder field inside: ρR^2/2rε Cylinder field outside: ρr/2ε Field generated by the wire: λ/2πr I should break the fields into components but I don't...

Hello! So I need to find the potential function of this Vector field $$ \begin{matrix} 2xy -yz\\ x^2-xz\\ 2z-xy \end{matrix} $$ Now first I tried to check if rotation is not ,since that is mandatory for the potentialfunction to exist.For that I used the jacobi matrix,and it was not...