All Questions
Tagged with electromagnetic-radiation conductors
40
questions
31
votes
8
answers
11k
views
If air is a bad conductor, how does fire heat up a room?
If air is a bad heat conductor, how does fire heat up a room?
Could someone help me, as I really don't get this?
- 451
5
votes
2
answers
2k
views
Are cars really Faraday cages: An anomalous observation
Background: A Faraday cage is essentially an enclosure of a conducting material. According to electrodynamics, signals cannot pass into or out of this enclosure, because when a signal approaches the ...
- 1,395
5
votes
1
answer
3k
views
What causes the phase difference between electric and magnetic fields of an EM wave in a conductor?
When an EM wave travels inside a conductor , we find that there is a phase difference between the Electric and magnetic fields within the conductor. The magnetic field lags behind the E field and ...
- 1,581
4
votes
1
answer
537
views
How far do electrons go in an antenna?
Do you know what is the distance electrons cover in an antenna during the production of a radio wave?
Does the extension of the oscillation vary with the frequency or the power of the radiation? Is ...
user137879
4
votes
3
answers
306
views
Why do we use wires/conductors to transport energy?
I am currently studying Maxwell equations and I learned that copper wires are essentially just wave guides for EM waves. Why do we not use an insulator to guide the wave and transport the energy which ...
- 225
3
votes
1
answer
618
views
Electric and magnetic fields boundary conditions
For a perfectly conducting and perfectly dielectric interface, I understood that tangential component of electric field is zero and continuous. But I have read that the normal component of magnetic ...
3
votes
6
answers
6k
views
How does the magnetic field always lag the electric field in a conductor?
In a conductor, the relation between the phase of the magnetic field $\delta_B$ and that of the electric field $\delta_E$ is given by $$\delta_B-\delta_E=\tan^{-1}(\frac{\beta}{\alpha})\tag{1}$$ where ...
- 26.8k
3
votes
1
answer
12k
views
How can electromagnetic waves reach a cell phone in Faraday cage?
is there any way to make electromagnetic waves reach a cell phone in Faraday cage although conductor surround cell phone everywhere? can we pass current through conductor to make charges move as a ...
- 99
3
votes
0
answers
64
views
Can cell phones send message in the elevator?
From Gauss's theorem, a closed, hollow conductor shields its interior from fields due to charges outside, but does not shield its exterior from the fields due to charges placed inside it. So my ...
- 267
3
votes
1
answer
164
views
How do you tell whether charges oscillate in the antenna because of an electric or magnetic field?
The electrons in a receiving antenna oscillate, can we establish if they respond to an electric or a magnetic field?
How can we know if there is an electric field apart from the one caused by the ...
user137879
2
votes
2
answers
423
views
Why are 'low frequency' EM waves attenuated by a single layer of kitchen foil?
Can someone explain why my am radio doesn't work when covered by a layer of foil that is less than one 'skin depth' at the appropriate frequency?
According to wikipedia and other websites on the ...
- 57
2
votes
1
answer
529
views
Do induced currents in a conductive surface result in significant electromagnetic fields outside the surface?
Consider the situation of a plane electromagnetic wave in vacuum incident normally on an interface with a good conductor. Within the conductor there is a small transmitted electric field (proportional ...
- 133k
2
votes
1
answer
2k
views
Skin Effect Explanation
I do not understand some things about the Skin Effect.
Its Wikipedia definition is:
Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor ...
- 1,319
2
votes
2
answers
84
views
How are neutral conductors neutral even though they microscopically aren't?
When dealing with electromagnetic waves inside conductors we take $$\nabla \cdot E = 0$$
and I believe we use the fact that conductors are neutral to do this. However, even though conductors on ...
- 320
2
votes
1
answer
396
views
EM-wave equation in conductors with source terms
The traditional modified Maxwell's equations to express em wave inside conductors that I have come across are:
$$
\nabla\cdot\mathbf E = 0
\\\nabla\cdot\mathbf B = 0
\\\nabla\times\mathbf E = -\frac{...
- 6,636