Faraday Definition and 207 Threads

Would a faraday cage block all types of radar?

Ok I'm trying to calculate the Dual Faraday Tensor, but I'm having trouble with the notation I think... *F^{ab} = \frac{1}{2}E^{abcd}F_{cd} where E is the levi-civita symbol. I'm correct in that E^(1234) = 1 for (1234,3412,2341,4123) -1 for (4321,3214,2143,1432) 0 otherwise...

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The EMF for the Faraday disc is calculated as \epsilon = \int_0^R \textbf{v} \times \textbf{B} \cdot d\textbf{l} the integration is between the disc axis (0) and its edge (R is the disc radius). As for uniformly rotating disc \boldmath v = \omega \times r and B-field is orthogonal to the...

Hello everyone, I need help designing a Faraday Generator suit. It's basically a bunch of small Faraday generators (the kind used in flashlights), sewn into the fabric of outer clothing and connecting to batteries to charge them. The problem is that I have no idea what it will take to make...

Hey there, I was wondering whether the following scenario is possible: Say I have a Faraday Cage which contains electricity on the inside, could I use a magnet on the outside to create electricity on a conductor on the inside? If no, are there possible variations to this scenario which...

Hello, I have constructed a Faraday box with alluminium sheets having holes on them. The problem is that the mains supply field is not canceled within this box. The box is about 50cmx50cm and hosts a number of electrodes and an electrical drive that moves these system of electrodes. I...

I'm working on a project that has a 13.56 MHz RF power source. The thing is, the EM waves emitted by this power source cause problems with the diagnostic equipment of the actual experiment (various capacitive and inductive sensors). So, I am planning to build a faraday cage to shield the...

Most places I've read say it's because the car forms a Faraday cage, but a few say that is incorrect and that it's actually from the skin effect. The notable case of the latter explanation is from the Boston Museum of Science: http://www.mos.org/sln/toe/cage.html This guy, Dr. Davis from the...

I'm working in a tracking solution based on RFiD, that consists on tags without any type of battery or power source. When the antenna generates the signal in the correct frequency, an induction process occur in the tag, generating a response to the antenna (containing the tag's id number)...

Hello. So I need a little bit of help with this. I am trying to 'make' a theoretical generator, that is powered by a wind station. There are so many variables that I either need to make up or find, such as coil thickness, length etc. So I was wondering whether anyone could help me? Can someone...

When this guy gets inside the Faraday cage and they hit it with like 200,000 volts from a Tesla coil , when he is inside the cage he can touch the inside and not get shocked , so basically the charge flows on the outside , is this because the electric field from all around the circle pushes...

Apologies for the atrocious attempt at a drawing: So my professor said that if you close the switch, the upper lightbulb (n° 2) will go out. How exactly do you know this? Well of course, if you replace the changing magnetic field that is inducing an emf with a battery somewhere close to...

Hi everyone! I was thinking..then I decided to post this thought to ask your opinion about that. We have this capacitor made by different layers, starting from the top we have: electrode, dielectric material (let's assume 10um thick, permittivity k=600), conductive layer (good liquid...

The non-conservative nature of an induced E-field due to a changing magnetic flux has always interested me. In the case of a constant magnetic field and a circuit with a changing surface, the changing magnetic flux can actually be written as a line integral of v x B (*), with v the speed of the...

Homework Statement A particle of charge q and mass m is traveling in the lab with velocity v in the x direction when it encounters a constant E-field in the y direction. State the non zero components of the Faraday tensor in the rest frame of the lab. The Attempt at a Solution I said...

Hello, a full contraction of the faraday tensor with itself can be shown to be F_{\mu\nu}F^{\nu\mu}=2(E^{2}-c^{2}B^{2}) I have done this by calculating 16 terms in the sum i.e. F11F11 + F12F21, and get this answer, but this is very tedious. Is there a faster way to show this that I...

Homework Statement I used a Faraday Rotator to measure the Verdet constant of SF-59 glass at 650 nm wavelength. In this setup, the glass sample was placed inside a solenoid, and a diode laser was aligned to enter the solenoid and go through the sample. The angle of rotation of an analyzer...

Hi everybody. Some expert advice needed here. I am working into an experiment that consists of putting a wave emitter device (a wi-fi router for example) in a faraday cage so those waves don't spread outside the cage (or I get some attenuation at least). I have some questions: - First of...

Please see the attachment. There I have derived Kirchhoff's Voltage law from Faraday's Induction law. Reply me if I have done something wrong and also notify me if this proof has been made somewhere else. Thanking you, EMROZ

Homework Statement I am trying to build a faraday flashlight and I need to know if this generator would work. Homework Equations I added a rough diagram to help illustrate this...3. The attempt at a solution I have a DIA20 x L10 cylindrical Neodymium magnet moving up and down inside a plastic...

pleasezzzzzz anyone can clear me on this point: [SIZE="4"]why -ve sighn comes in faraday law of electro magnetic induction?what is it sighnificance?if in answer value of induce EMF become -ve than waht will be its direction.

Hi, I read several literatures on quantum cryptography plug and play system. I found out that Faraday mirror was used to compensate polarization fluctuations. Photons are reflected orthogonally by Faraday mirror and their polarization changes will then be autocompensated, provided they follow...

Well we can use a Faraday Cage to keep magnetic fields from entering a certain area, but I was wondering if the same method could work for containing magnetic fields. I know we use metal cores to concentrate magnetic fields, but is there a way to actually trap them?

in the following question i am given an infinite straight wire with a current changing according to i=2t, next to the wire is a conducting square with a side of a=5cm at t=0 the square is at a distance of b=5cm from the wire and the frame is moving away from the frame at v=2m/s, the frame has a...

I have this equation and the following values for a transformer Bmax= (V1)/(4N1fA) V1=10v, i.e. 20v peak-to-peak N1=40 turns f=5000Hz A=76x10-6 m2 When i substitute in the voltage, do i use the 10v, or the peak to peak, or would i have to convert to Vrms

Homework Statement A long solenoid of radius a , is driven by an alternating current , so that the field inside is sinusoidal: B(t)=B0cos(omega*t)z-hat. A circular loop of wire, of raduis a/2 and resistance R, is placed inside the solenoid and coaxial with it. Find the current induced in the...

1. Suffer extreme symptoms from Microwave RF emissions cell phones, Wi FI, Cordless computers and RF Routers. 2. The next door neighbour has installed a Uniden DECT that transmits continually 24 hours a day. Our bedroom and the next door neighbours loungeroom is separated by a normal...

Homework Statement I need to build a faraday flashlight and I have two problems. Homework Equations (1) When I use a 12V DC motor connected in parallel to a capacitor (16V 2200uf) and then to an LED assembly, I can't get the capacitor to charge. (2) If I wanted to use a magnet and coils...

Hello, What do i substitute the 'd' and 't' for in this equasion: It just didnt say, so i am a bit lost!

Homework Statement I ave a research to do on Faraday effect. I found an explanation were they said that a linearly-polarized beam of light may be considered as the superposition of equal amounts of right- and left-circularly polarized beams. The right- and left-circularly polarized beams or...

[SIZE="1"]Couple of months ago Deany100 posted a note on microwave radiation which he suspected was his neighbour tracking his movements. I've got a similar problem, a home bathed in emf picked up by a device (15 pounds sterling) that doesn't tell me what the frequency is. Great disbelief from...

I have a few questions and verifying statements regarding the concept as well as practical building of Faraday Cages. 1. A Faraday cage's mesh must have a grid with a spacing less than that of the wavelength that is intended to be stopped. 2. Why is it that foil and mylar also work as...

A circular coil, with radius of 10 cm, and 25 turns, rotates in a constant magnetic field of strength 2.4 T, with the axis of rotation perpendicular to the direction of the magnetic field. If the coil rotates at a frequency of 50 Hz, what is the induced peak voltage? Okay so I know the...

Homework Statement Hi all. I can't seem to understand how to apply Lenz' law to a disc rotating in a magnetic field that is perpendicular to the discs plane (see first page on PDF): http://www.pa.uky.edu/~latimer/phy232s08/lectures/phy232l31_4.pdf I can see that using the right-hand...

Homework Statement For my physics project I decided to make a Faraday cage to cancel out cell phone signal. Homework Equations The Attempt at a Solution For my first attempts at making a successful project I used chicken wire and wire mesh to make a cylindrical cage. Our goal was...

Dear readers! I wanted to arrange a little demonstration for my relatives with my cellphone inside a Faraday cage. Of course I expected no EM waves to be present inside the cage, which means that my cellphone wouldn't ring when being called. Well, we repeated the experiment several times...

Hi, I have problems with charge distributions of buckets and other conductors which has a cavity. If there is experiments, photos, detailed examples about this kind of charges then glad to learn the links in net. Suppose have a conductor like Faraday ice bucket. And tied two un-charged...

I have a question regarding Faraday Cages... Faraday Cages blocks static electrical fields I read somewhere that static magnetic fields can penetrate the faraday cage when changed slowly. Faster changes in static magnetic fields cannot penetrate a faraday cage, is this true? Also does...

Hi! I want to know what will happen if I insert current (moving electrons) into Faraday cage, which is ungrounded? Will still there be no electric field, inside the cage?

Can external current pass through Faraday cage,like thunder? Will be there electrical field, inside the Faraday cage?

[SOLVED] Faraday cage problem A man is standing on a rubber mat which is isolated. You place a Faraday Cage around the mat. (the cage is standing on top of the mat) The man is touching the cage Now when lightning hits will: 1) the cage be loaded with electricity 2) the cage not be loaded...

Hello all, I plans to reduce RF strength in my apartment by cover the room with conductive material. - Cover 2 walls which facing the boardcasting tower. - Cover the floor and ceiling. Total 4 sides (since the material is quite expensive) Then I'll grounded them to the apartment...

i heard that a faraday cage is often used in shielding e.g. sensitive electrical equipment. I was just wondering, because, in http://socrates.berkeley.edu/~fajans/Teaching/cartoons/Shielding/TestChargeShielding_files/frame.htm it seems that the electric field is not zero at ALL times. i.e...

I've looked this up extensively on the web but nothing seems to answer this question satisfactorily. For example, here's Wikipedia's answer. I try thinking of it considering the properties of a conductor in electrostatic equilibrium. The charge on a conductor in equilibrium resides on the...

hi. I am currently supposed to be doing a lab on the faraday effect, however the lab manual provided was poorly written and some what clumsy in the experimental procedure. I was wondering if any of you know a good site or book that explains a little about the theory and how experamental...

The Faraday two form is a two form on pairs of four dimensional vectors (3 space +1 time). It is given by(may I be forgiven for the notation): F = E_x dx\wedge dt + E_y dy\wedge dt + E_z dz\wedge dt + B_z dx\wedge dy + B_x dy\wedge dz + B_y dz\wedge dx Most books then go on to say that for...

http://img212.imageshack.us/img212/2931/energyplan26qs.th.png There is my uh rudamentary drawing of a scenerio where something emitting em waves(green) is surrounded by a faraday cage(yellow). umm I believe current is induced in the 'cage', how would I divert the current to use, because if I...

Lets say, hypothetically of course, that i know somebody that had something that, with that something being charged, was generating a strong electric field(or maybe electromagnetic waves?) that was emitted in all directions for infinity, if this hypothetical friend were to put a faraday cage...

Hi, We know that in a space region free from electric charges and surrounded by a conducting surface, the electric field must be zero (this is the Faraday cage). I suspect that this statement can be derived directly from the Maxwell equations, but I don't find this derivation anywhere...