[hamdani yusuf (OP)]

Impedance matching in mechanical wave.

[alancalverd]

These videos show that energy transfer by radiation can be passed through material as well as being absorbed.

Good heavens! Whatever will those crazy scientists discover next? Are air, water and glass transparent? Can x-rays pass through the human body?

Truly it is a privilege to live in the 21st century when, thanks to the miracle of the internet, we can be amazed by what our parents considered to be bloody obvious.

[hamdani yusuf (OP)]

Most of us know that impedance is frequency dependent. Mathematical model for impedance is a complex number. Thermodynamics and black body radiation seem to consider only the real part of this impedance. That's because in those cases, the imaginary part is not significant. They're only special cases from the more general cases where the radiating or radiated bodies are not necessarily black body.

It's understandable that scientific research started with simpler cases. But let's not forget that there are more than what earlier discovery has told us.

[hamdani yusuf (OP)]

Good heavens! Whatever will those crazy scientists discover next? Are air, water and glass transparent? Can x-rays pass through the human body?

You seem to forget that water and typical glasses are not transparent in infrared spectrum.

[alancalverd]

I am well aware of the absorption spectrum of water, as should be anyone with an interest in meterorology and climate change. Unfortunately the makers of infrared heat lamps do not share your profound knowledge!

Transparency does not imply zero attenuation at all frequencies, just usefully low values at important points on the spectrum.

[Bored chemist]

Most of us know that impedance is frequency dependent. Mathematical model for impedance is a complex number. Thermodynamics and black body radiation seem to consider only the real part of this impedance. That's because in those cases, the imaginary part is not significant. They're only special cases from the more general cases where the radiating or radiated bodies are not necessarily black body.

It's understandable that scientific research started with simpler cases. But let's not forget that there are more than what earlier discovery has told us.

You have that more or less exactly wrong.
The imaginary part of the refractive index relates to absorbing light.(And thus BBR) But  the real part relates to the wavelike properties of the light that carries on or is reflected.

"Light propagation in absorbing materials can be described using a complex-valued refractive index.[2] The imaginary part then handles the attenuation, while the real part accounts for refraction"
From
https://en.wikipedia.org/wiki/Refractive_index

Did you consider learning science (rather than just watching YT)?

[hamdani yusuf (OP)]

Unfortunately the makers of infrared heat lamps do not share your profound knowledge!

A good absorber is also a good emitter in the same spectrum. That's where infrared heat lamp can optimize it.
But lower frequency radiation should also be considered.

Short video about the importance of grounding your heat lamp.

[alancalverd]

Why? It's pretty obvious that a conductor carrying a couple of amps at 50 - 60 Hz is going to radiate em. The question is whether that actually matters in the context of all the other current carriers in the  house.

LED lamps obviously emit less because they are DC-powered, but if you obtain that power from the mains, you are probably emitting 100 kHz  from the switch-mode power supply.

[Bored chemist]

Unfortunately the makers of infrared heat lamps do not share your profound knowledge!

A good absorber is also a good emitter in the same spectrum. That's where infrared heat lamp can optimize it.
But lower frequency radiation should also be considered.

Short video about the importance of grounding your heat lamp.

What "point" are you trying to make here?

[paul cotter]

That is absolutely ridiculous, EMF from a filament lamp. Whatever minimal 50/60hz EMF the lamp produces would not be affected at all by any earthing(grounding) protocol unless the lamp was encased in metal, which would render it useless. Where the hell do these infantile videos come from?

[Bored chemist]

It's perfectly plausible that the cord of a lamp is making a passable antenna to transmit some RF noise from the mains and the earth cord (or the design of the lamp with more metalwork) is attenuating that.

And incandescent lamp is basically a coil of wire, it's going to generate a magnetic field when you use it.

The big question is...
Who cares?

[paul cotter]

The two conductors would be carrying equal and opposite currents which at that low frequency would lead to effective cancellation with the earth(ground) wire performing no function in the absence of a fault. What minute amount of radiation results could be eliminated by a screened feed cable. As you say, who cares?

[hamdani yusuf (OP)]

Most of us know that impedance is frequency dependent. Mathematical model for impedance is a complex number. Thermodynamics and black body radiation seem to consider only the real part of this impedance. That's because in those cases, the imaginary part is not significant. They're only special cases from the more general cases where the radiating or radiated bodies are not necessarily black body.

It's understandable that scientific research started with simpler cases. But let's not forget that there are more than what earlier discovery has told us.

You have that more or less exactly wrong.
The imaginary part of the refractive index relates to absorbing light.(And thus BBR) But  the real part relates to the wavelike properties of the light that carries on or is reflected.

"Light propagation in absorbing materials can be described using a complex-valued refractive index.[2] The imaginary part then handles the attenuation, while the real part accounts for refraction"
From
https://en.wikipedia.org/wiki/Refractive_index

Did you consider learning science (rather than just watching YT)?

What makes you fail to distinguish between impedance and refractive index?

[Bored chemist]

What makes you fail to distinguish between impedance and refractive index?

The fairly close relationship between them.
The impedance is sqrt(  permeability /permittivity).

And (for non magnetic materials) the dielectric constant is the square of the refractive index.

Light reflected from a window is an impedance mismatch effect.

Were you aware of this?
https://en.wikipedia.org/wiki/Clausius%E2%80%93Mossotti_relation

[hamdani yusuf (OP)]

Why? It's pretty obvious that a conductor carrying a couple of amps at 50 - 60 Hz is going to radiate em. The question is whether that actually matters in the context of all the other current carriers in the  house.

It depends on the shape of the conductors, whether it will act like an antenna, or more like a Faraday cage.

LED lamps obviously emit less because they are DC-powered, but if you obtain that power from the mains, you are probably emitting 100 kHz  from the switch-mode power supply.

That oscillation can be radiated to its surroundings. It can affect the temperature measurement of some types of thermometers, especially the electronic ones.

[hamdani yusuf (OP)]

Were you aware of this?
https://en.wikipedia.org/wiki/Clausius%E2%80%93Mossotti_relation

Not the exact formula. But my experiments with microwave and metamaterials suggest that refractive index depends on the unit density of metamaterial and polarizability of the metamaterial unit.

[Bored chemist]

Why? It's pretty obvious that a conductor carrying a couple of amps at 50 - 60 Hz is going to radiate em. The question is whether that actually matters in the context of all the other current carriers in the  house.

It depends on the shape of the conductors, whether it will act like an antenna, or more like a Faraday cage.

LED lamps obviously emit less because they are DC-powered, but if you obtain that power from the mains, you are probably emitting 100 kHz  from the switch-mode power supply.

That oscillation can be radiated to its surroundings. It can affect the temperature measurement of some types of thermometers, especially the electronic ones.

Why do you keep stating the obvious?

[hamdani yusuf (OP)]

Why do you keep stating the obvious?

Because there are someone who keep overlooking it.

[Bored chemist]

Are you saying we shouldn't ignore small effects?

[hamdani yusuf (OP)]

Are you saying we shouldn't ignore small effects?

We won't know if the effects were small until they are measured, or at least calculated.