[VNandor]

Does someone actually know how far electrons travel at 60hz AC in one half cycle? i mean, some talked about electrons "wiggling" around (i would assume a few mm here) but 1/120 of a second is probably much larger distance for electrons than a few mm

Edit: So with electrons traveling at 300.000km / s .... 1/120 of that is 2,5km, so could we assume with AC electrons travel 2,5km before they turn around?

No, the electrons don't travel anywhere near at the speed of light, so we can't assume that the "electrons travel 2,5km", whatever that means in your insane word.
http://amasci.com/miscon/speed.html

 

[Ghoostknight]

And about AC... how far do the electrons move as they vibrate back and forth? Well, we know that a one-amp current in 1mm wire is moving at 8.4cm per hour, so in one second it moves: 8.4cm / 3600sec = .00233 cm/sec

And in 1/60 of a second it will travel back and forth by = .00233cm/sec * (1/60)
= .0000389cm
or around .00002 in.

interesting.

 

[bfreedma]

We’ve got ourselves a real Nikola Edison posting in the thread…

 

[Ryokan]

'A radio wave travels at the speed of light in a vacuum. Marconi transmitted the first transatlantic radio message in 1901. A very tiny amount of his message has reached a point 119 light years from Earth'.
Aug 2021

Will these waves keep going indefinitely, why only a tiny amount?

 

[danadam]

why only a tiny amount?

Inverse-square law I presume.

 

[Ryokan]

Inverse-square law I presume.

But the source stopped emitting soon after it was transmitted? Isn't that more relevant to a light source, such as a star?

 

[castleofargh]

But the source stopped emitting soon after it was transmitted? Isn't that more relevant to a light source, such as a star?

In this context, they're the same thing, electromagnetic waves at different frequencies.
When you move further away from a Bluetooth or Wi-Fi source you get the same impact(plus walls which are rarer in space ^_^).

 

[Ryokan]

In this context, they're the same thing, electromagnetic waves at different frequencies.
When you move further away from a Bluetooth or Wi-Fi source you get the same impact(plus walls which are rarer in space ^_^).

So different size antenna's would be needed to detect different frequencies? The lens on the James Webb telescope has a diameter of 6.5m, if it was detecting radio waves of the same distance it detects light it would need to be considerably larger?

 

[danadam]

But the source stopped emitting soon after it was transmitted? Isn't that more relevant to a light source, such as a star?

More relevant? I guess that depends on what weights you assign to the attenuation (due to the inverse-square law) vs duration of the signal . They both will be attenuated the same way. The long-lived signal will be easier to detect/extract from the background noise than a short-lived "blip" that passes you only once.
(At least that's how I understand it, but I'm not an astronomer )

 

[TYATYA]

Does someone actually know how far electrons travel at 60hz AC in one half cycle? i mean, some talked about electrons "wiggling" around (i would assume a few mm here) but 1/120 of a second is probably much larger distance for electrons than a few mm

Edit: So with electrons traveling at 300.000km / s .... 1/120 of that is 2,5km, so could we assume with AC electrons travel 2,5km before they turn around?

You checked your health recently??
You ask an electron inside accelerator??

 

[castleofargh]

So different size antenna's would be needed to detect different frequencies?

Ideally, yes, the antenna would be related to the wavelength we're trying to capture(at least I think it's the same for emission and reception, but it's clearly not something I'm understanding well so I might be full of crap). Note that most considerations are in an attempt to get something smaller because otherwise the antennas would get ludicrously huge. If you can make one even bigger, it's probably better.

The lens on the James Webb telescope has a diameter of 6.5m, if it was detecting radio waves of the same distance it detects light it would need to be considerably larger?

Same thing. The main issue tends to be the intensity of the signal we're getting. For optical devices, the bigger the lens the more light can be focused into a single point and the brighter that point will be on the sensor/eye. It's not about the wavelength of the signal. The JWST works down to infrared, and even that is less than half a millimeter. The size in such a case is clearly about gathering a bigger surface into a given area to increase brightness.

 

[TYATYA]

Is there a point to this?

He still thinking once the red turn to green, those cars travel at 747's speed just because he see all cars move simulanously.
If those are not cars but snail (smart snail understand traffic light signal), he may think theres no electricity because snail is too slow

 

[TYATYA]

Once forgot or misunderstanding what teachers told you, can remind yourself by seeing array of cars infront of signal light.
Speed of ligh (R, G signal) is that speed of electromagnetic transmission. Cars speed is not light speed.
Dont waste you brain think that flow of cars fast as green light signal just because you see the car at the end moves same time with the 1st place car

 

[gregorio]

interesting.

Why is it “interesting”? The only reason I can think why it might be interesting is if someone falsely believes electricity is the flow of electrons and therefore electron speed/movement is somehow relevant. If that were actually the case, then when you flipped the light switch in a DC circuit with 2 meters of cable, it would take about a day until the light bulb would actually turn on and in an AC circuit it would never turn on (as there is no net movement/flow of electrons). Once you understand that electricity is actually an electromagnetic field, then the movement/speed of the electrons themselves is irrelevant and therefore not “interesting”.

So with electrons traveling at 300.000km / s .... 1/120 of that is 2,5km, so could we assume with AC electrons travel 2,5km before they turn around?

Unfortunately, this demonstrates you are not able to understand that electricity is an electromagnetic field, still believe it is the movement/speed of electrons despite the evidence and explanations presented/linked and therefore what you think “we could assume” is incorrect by a factor of about six billion times. That’s impressive even by audiophile standards! lol

I’m curious though, how do think electrons “travel 2.5km before they turn around” in power cable that’s 2m long? lol

G

 

[bigshot]

Wake me up when we start talking about home audio again.