# Search results

• Users: Gh778
• In Electromagnetism
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1. ### Does this device give a magnetic field?

Ok, and to have the magnetostatic field ?
2. ### Does this device give a magnetic field?

Sorry, but I don't undertand how to use your link to find the magnetostatic field, could you explain please ?
3. ### Does this device give a magnetic field?

It's only for one particle ? And I'm looking for the magnetic field at low frequency not the electromagnetic wave.
4. ### Does this device give a magnetic field?

Hello, It's a theoretical question. I take 2 electrostatic particules fixed in a circle. I turn the circle. Is there a magnetic field ? I suppose the angular velocity very high and I suppose the particules are fixed in the circle. The diameter of the circle is very small. I don't want the...
5. ### Faraday cage in a parallel plate capacitor

With a circular capacitor and a semi circular Faraday cage, the force to move up (not collapse) the cage is up (like drawing) and this go down the capacity. Sure we can't move a high distance. I give 2 femm files for test. The "az4" file is the capacitor at start when I'm charging it. We can see...
6. ### Faraday cage in a parallel plate capacitor

I'm trying to understand why my intuition is false and in the same time I'm learning physics because I like it:) For now, like I don't know how to calculate I do some simulations with FEMM 2D software. You're right with my dimensions the force need energy. If I modify dimensions the force...
7. ### Faraday cage in a parallel plate capacitor

If I use your links, I considered circular surfaces for capacitor and Faraday cage. I integrate from 0 to 40 mm I find: 950-173-133 for the sum of force (at a factor near). From 0 to 40 mm for 2 mm distance = 950 From 0 to 40 mm for 9 mm distance = 173 From 0 to 40 mm for 11 mm distance = 133...
8. ### Faraday cage in a parallel plate capacitor

I don't understand, could you say each surface of Faraday cage is not attracted from nothing ? Note the capacitor has not an infinite surface, considered it like 40mm*40mm for example, this is considered like infinite ? Even there is no force, the capacitor has gain energy when the Faraday has...
9. ### Faraday cage in a parallel plate capacitor

Ok, you're right the charge on surface of the Faraday cage is the same than capacitor. In this case if I collapse cage to itself it's easy to see this give energy: Ff > Fl+Fr
10. ### Faraday cage in a parallel plate capacitor

So, the charge on each surface (capacitor or Faraday cage) is the same ? Even thickness of Faraday cage is 2 mm compared to thickness of capacitor 20 mm ? It's not 1/10 of the charge because Faraday cage cancel only field which seeing by itself ?
11. ### Faraday cage in a parallel plate capacitor

With: d=2mm thickness of Faraday cage D=20 mm thickness of capacitor S surface of capacitor and Faraday cage U=voltage input for charged capacitor Vacuum everywhere else Could you at least give me: Charge and field E of capacitor at start when Faraday cage are in it ? Charge on the...
12. ### Faraday cage in a parallel plate capacitor

I would like to verify by myself if it's possible ? For me, the short distance of the Faraday surfaces compared to distance from capacitor would give energy, I would be happy to understand with calculations how this is false.
13. ### Faraday cage in a parallel plate capacitor

Ok, how I could calculate the work need to move close surfaces of Faraday cage ? Could you help me for that ?
14. ### Faraday cage in a parallel plate capacitor

When the Faraday cage is in the capacitor the gap is lower for me because it's like have 18 mm. But after collapse Faraday cage we have 20 mm, like d increase the capacity is lower so the energy greater ? I'm trying to understand.
15. ### Faraday cage in a parallel plate capacitor

Imagine the capacitor without Faraday cage is has 20 mm of air. Now, the same capacitor with Faraday cage don't see 18 mm of air because relative permittivity of iron is high ? At first, we have 18 mm of air at final we have 20 mm of air, this don't go down capacity ? You're right there is...
16. ### Faraday cage in a parallel plate capacitor

It's for that I wrote 10 times charges for capacitor in the simple formula. If cage is 2 mm and capacitor 20 mm, the charge on cage is not 1/10 of charge on capacitor ? yes, I want to see energy when collapsing the cage. I don't understand your sentence, there are another forces than cage or...
17. ### Faraday cage in a parallel plate capacitor

Ok, if the Faraday cage is large but with 2mm of thickness for the cage and 20 mm for the capacitor. One surface of the cage is at 2 mm to another but at 9 mm to capacitor surface (other at 11 mm). Like force is in 1/d² we don't have something like that for one surface: 1/2²-10/9²-10/11² ...
18. ### Faraday cage in a parallel plate capacitor

I don't understand where I'm wrong, I details: 1/ A plate capacitor has like dielectric a Faraday cage with thin wall, all is fixed. The capacitor is 20 mm and the Faraday cage is 2 mm in the center of the capacitor, elsewhere there is air 2/ Charge with U voltage, all energy lost from source...
19. ### Faraday cage in a parallel plate capacitor

Ok for the infinite permittivity of Faraday cage but where energy is lost when I move close surfaces of Faraday cage ? If the cage has a thin thickness, it's possible to recover energy from move close its surfaces and in this cage capacity of capacitor decrease and so energy go up ?
20. ### Faraday cage in a parallel plate capacitor

Sorry, I'm not fluently in english Charge a plate capacitor which has 1mm of thickness and a dielectric like teflon (relative permittivity of 60). Cut source voltage. Envelop all teflon of thin iron. The iron reduce thickness to 0.1 mm but now the relative permittivity is 1 not 60. At final the...
21. ### Faraday cage in a parallel plate capacitor

A plate capacitor has a dielectric of 60 inside with 1 mm of thickness. We charge it from external voltage source. When charged cut the source. Move in a Faraday cage which envelop the dielectric (without touch conductor), this decrease the thickness to 0.1 mm for example but the capacity go...
22. ### Faraday cage in a parallel plate capacitor

ok, like the energy go down I think we win energy from move Faraday cage, but there is no charge in the cage, how energy is win ? Edit: I just understand that there is charges in cage, so we win energy from attraction. In this case, I can place Faraday cage, cut it (in the length) inside plane...
23. ### Faraday cage in a parallel plate capacitor

Hi, A parallel plate capacitor is charged from fixed voltage, after I cut voltage source. Now, what's happened if I place a Faraday cage inside capacitor (without touch capacitor) ? Capacity changed ? So energy of capacitor changed ?