Homework Statement
We have an incident electric field, and there are two cases:
1) the field is polasised perpendicularly to the incidence plane (TE)
2) polarised in the plane (TM)
Here I must be able to correctly apply the limit conditions, to find the Fresnel formulas that give the...
Homework Statement
A laser tweezer is a laboratory instrument, which uses highly focused laser beams to ‘trap’, hold or move small sized objects. The principle of the operation is that in the focal spot, the light intensity is inhomogeneous, and acts on the particle with a force that points...
So I'm kind of confused. The way I understand it, an electromagnetic field is just a regular electric field viewed from a relativistic point of view, meaning that since we see the charges moving relative to us, we feel like the particles and the fields created by them come closer together (I...
Susan Pocket claims that part of the electromagnetic field of the brain is consciousness and that conscious qualities such as a red car are spatially patterned electromagnetic fields. She also claims that the quantum spatial scale is irrelevant. Intuitively it seems to me Quantum electrodynamics...
Why does my laptop's screen refresh every time I bring a metal object (any size) to my electric lighter?
-Happens when I am 1 foot away from the laptop
-1 foot away from the external monitor's wires (HDMI & power)
1. Video footage (MUST WATCH)
NOTE: the laptop screen also flickers a bit
NOTE...
Homework Statement
A metal rod can slide on a rail without any friction in the presence of uniform magnetic field of B=1T which is perpendicular to the plane of the paper.The distance between the tracks is d=0.1m and the resistance given is R=0.1 ohm.The resistance of the rail is negligible and...
As I understand it, light is an electromagnetic wave consisting of an oscillating electric and magnetic fields perpendicular to each other.
Are there experiments that will demonstrate (a) there is an electric field present? Stark effect? (b) a magnetic field, (c) that they are perpendicular to...
Hi. This might be really basic. But I am really struggling to grasp the difference between electrical currents such as AC and DC and RF. For the case of AC current, it alternates currents at a certain frequency.. which makes me wonder how AC and RF are different.
Also, if you could, could you...
Hi everyone!
I've been reading about these topics (Feynman lectures and more on the internet and some books) but I still have a doubt, maybe because I haven't understood the whole of it.
This is my doubt: Think of an imaginary situation in which we have an accelerating charge. The...
Dynamos and transformers have inductor coils reacting with changing magnetic fields and importing energy into the circuit in form of induced current
1. What about the counterpart of above principle in case of capacitors?
2. Will capacitors interact with...
Hi! For project in one of my classes, I have to research a super power and a possible scientific explanation of it, showing either why it can or can't happen. I chose a super power of translating people's electro magnetic fields into frequencies, and being able to translate that into...
The common presentation for free field quantization proceeds with the Lorentz and Coulomb (##\phi = 0, \,\nabla \cdot \mathbf{A} = 0 ##) constraints. Then ##A## can be defined
$$\mathbf{A} \propto \iint \frac{d^3 p}{\sqrt{2\omega_p}}\sum_{\lambda} \Big(e^{i\mathbf{p}\cdot...
The momentum canonical to the electromagnetic vector field A is straightforward to compute, as is explained in textbooks or webfiles (for example Bjorken-Drell or http://www.physics.buffalo.edu/gonsalves/aqm/lectures/10/lec-10.pdf ). Its time component is zero, while the spatial components are...
Homework Statement
A uniform current sheet in free space is given to be, in phasor form, \vec{J}=\vec{x}J_0e^{-jk_1y} located at the z=0 plane. k_1 < k_0 where k_0 is the wavenumber in free space.
a) Describe qualitatively the characteristics of the wave generated by the given current source...
I know the ampere's law but I want an explanation on why it exist in that way, consider a wire where flows current, i know that when an observer is in relative motion to the current there is a magnetic field but why in this geometric configuration and not in another? What about the electric...
Hello everybody,
It is known that electric field operator is shown as
\hat{E}(r,t)=-i\sum_{k,\lambda}\sqrt{\frac{\hbar\omega_k}{2\epsilon V}}\left(a(t)^\dagger_{k,\lambda} e^{-ik.r} - a(t)_{k,\lambda} e^{ik.r} \right) \hat{e}_{k,\lambda}
But if I need to represent an electrostatic field in a...
This question is a continuation/topic-extrapolation of:
https://www.physicsforums.com/threads/flux-in-magnetic-core-according-to-special-relativity.856482/#post-5374651
My question is 'how is the electromagnetic field different from some sort of mere electric-charge field?'
The issue I have...
Maybe a stupid question and maybe sensless to ask, but as I don't know, I ask anyway:
what is the length of the newly found gravitational waves in terms of traditional EM wavelengths?
In my electromagnetic theory book, there is a classification of vector fields, one of the 4 different type vector fields is "solenoidal and irrotational vector field" (both divergence-free and curl-free).
If solenoidal and rotational vector fields are same thing, then it means the vector field...
Homework Statement
Hi, so during an experiment, I spun a magnet inside a coil of wire in order to induce an emf, and measure the input power and output power. One of the things I found was that the slower the magnet spun (ie the smaller the input voltage to the motor) the larger the induced...
Hello.
I'm studying quantization of electromagnetic field (to see photon!) and on the way to reach harmonic oscillator Hamiltonian as a final stage, sudden transition that the Fourier components of vector potential A become quantum operators is observed. (See...
How can I compute the intensity of an electromagnetic radiation if I know ##e_x, e_y, e_z, h_x, h_y,## and ##h_z##, where ##e_i## is the electric field component at ##i## and ##h_i## is the magnetic field component, also at ##i##?
Thank you in advance.
Homework Statement
Find the magnitude and direction of net electric field at the center of the square array of charges. Find E_x and E_y
The square array of charges http://postimg.org/image/4gf94ymmf/
The Attempt at a Solution
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My attempt at drawing in the force vectors...
I need help explaining that this assumption is not correct or correct:
A product uses Radio waves to turn on a LED. Radio waves can be a form of electromagnetic fields therefore, a Hall Effect sensor could be used in this device to turn on that LED.
The book is expensive, so I want a book like Bekefi's and Barrett's Electromagnetic Vibrations,Waves,Radiation. Preferably at a higher level than this book.
Thank you!
Homework Statement
I have to expand the following term:
$$\dfrac{1}{4} F_{\mu\nu}F^{\mu\nu} = \dfrac{1}{4} \left(\partial_{\mu}A_{\nu} - \partial_{\nu}A_{\mu}\right) \left(\partial^{\mu}A^{\nu} - \partial^{\nu}A^{\mu}\right)$$
to get in the end this form...
Think about an electric charged object moves linely, it will produce current hence the magnetic field.
But if the obserser moves together with the electron charged object, so there is no relative movement between them, that means the electric charged object is static to the observer, hence...
The prevailing wisdom is that coiling excess signal cable under an MRI magnet for storage in a figure-8 configuration will reduce or eliminate induced noise onto the cable from the pulsing fields from gradient coils. I am starting to doubt this, however. A quick diagram of a figure-8 looped...
Hello all,
I'm working on a little side project to build something close to a Mag-lev system. I've researched loads around the magnets and have the info' on what conditions I need, current, Field strength, etc. But I'm having issues in finding how that relates to the movement of an external...