2
votes
3answers
373 views

How does the movement of electrons produce radio waves?

I'm mostly wondering about radio frequencies. I understand that voltage is the movement of electrons, and that the antenna acts as a light bulb, emitting at radio frequencies, following the reverse ...
1
vote
1answer
34 views

transfer of electricity through electromagnetic waves

Is it possible to transfer electricity from one place to another without the help of physical wires.
1
vote
0answers
50 views

Alternative solar panels

I was doing a bit of thinking recently, when I stumbled on an interesting idea. In a simplified sense, solar cells function by absorbing light and converting it into electrical energy. Since visible ...
0
votes
0answers
57 views

“+” and “-” sign in Maxwell Stress tensor

I have trouble in determining the "+" and "-" sign of momentum per unit time, per unit area of the following question. Why in the second part, $d\vec{a}$ is pointing in the $ -\vec{z} $ direction? I ...
2
votes
2answers
124 views

Why doesn't alternating current produce light while a vibrating single particle with a charge will

If a vibrating atom can produce light why can't an alternating current of electrons do the same? EDIT: When I use the term "light" I mean all EMR
1
vote
1answer
566 views

Why the electric bulb turns on almost instantly when the switch is closed? [duplicate]

The electron drift speed is estimated to be very low.How could there is current almost the instant a circuit is closed?? By the discussions it is known that The information about beginning of the ...
1
vote
1answer
108 views

What is the pressure of a gas required to ionize the gas using an electron gun?

How dense does a gas (Argon in particular ) have to be to in order to ionize it using electron bombardment and weak magnetic fields. Is there a correlation with the density of a gas and the easiness ...
4
votes
2answers
112 views

Applicability of the concept of voltage in electrodynamic circuits

In electrostatics, we have $$\nabla \times \vec{E} = 0$$. Hence, we can define a scalar potential $V$, where $$\vec{E} = -\nabla V$$. We know from Faraday's law that $$\nabla \times \vec{E} = ...
2
votes
3answers
302 views

Producing electricity from all wavelengths of electromagnetic spectrum

Is it possible to produce electricity from all wavelengths of electromagnetic spectrum beside visible light ?Like using gamma rays or x-rays .
3
votes
1answer
175 views

Why does electromagnetic waves travel slower in well isolated conductor?

Wikipedia writes, that Propagation speed is affected by insulation, so that in an unshielded copper conductor ranges 95 to 97% that of the speed of light, while in a typical coaxial cable it is ...
0
votes
0answers
96 views

what exactly do electric waves transfer from one point of the wire to other..? [duplicate]

Possible Duplicate: how does electricity propagate in a conductor? so basically i was considering the speed of the charges inside wire defined by the drift velocity and speed of electric ...
2
votes
2answers
3k views

Microwaves vs Gas or Electric Coil heating of a water boiler in a typical household

Wouldn't it be more energy efficient and or safe to use microwaves to heat our home's water boiler instead of using dangerous gas or hot electric coils that could catch other things on fire? I'm kinda ...
12
votes
7answers
4k views

Why is electricity not transmitted wirelessly?

Why is electricity not transmitted wirelessly such that we don't need to span cables on the earth's surface? As in: electricity is transmitted wirelessly from the power plant to the household.
7
votes
1answer
1k views

What’s the relationship between thermal radiation and Johnson thermal noise?

All objects above absolute zero emit radiation due to random collisions between the atoms they are made of. The spectrum of radiation emitted varies according to the temperature of the object, I ...