Ask any question you want about Physics

originally posted by: Bedlam

originally posted by: BASSPLYR
how's an led work?

The photons are screams from electrons falling into a hole.

How do the LED's keep forcing electrons into a hole to eject photons? Like how do they physically operate or are built? The mechanical mechanism they are using to achieve this with the diode. Power oscillations or something?

a reply to: Bedlam

Your last post. Is very interesting. I'm going to have to re-read it a couple of times to best digest it before I respond.




Starring each and every post for you guys as a way of saying thanks for trying to educate me a little and for taking the time. I know I'm a pest sometimes.

originally posted by: BASSPLYR
a reply to: Arbitrageur

Well on the picture you posted of wavelengths. It looked (and I could be wrong-usually am) that blue and purple were the least abundant of the visible spectrum. SO I was thinking if plants had a choice instead of being green and loosing the green wavelengths for fuel which I thought looking at the picture were more abundant. It would be better for plants to trade for rejecting blue and purple wavelengths and get the benefit of the slightly more abundant green. I dunno I was looking at the picture from my phone trying to blow it up while squinting at the screen on a bus ride to work.

Blue/UV would be the most energetic, so you might be able to get more ATP per photon. Probably had another molecule around to use for a red dye that fit the rest of the chloroplast. So maybe there's not a useful green/yellow dye that's easily evolved, or to get it you have to have massive changes to a system that already works well enough. So it's never come up.

originally posted by: BASSPLYR

originally posted by: Bedlam

originally posted by: BASSPLYR
how's an led work?

The photons are screams from electrons falling into a hole.

How do the LED's keep forcing electrons into a hole to eject photons? Like how do they physically operate or are built? The mechanical mechanism they are using to achieve this with the diode. Power oscillations or something?

Well, when you forward bias a diode, you remove electrons from the P side which creates holes, which stream toward the cathode. You add electrons to the N side, which move toward the anode. They meet in or near the junction on the P side, and the electrons fall into the holes. When this happens, the electron falls from the conduction band on the P material atom to the vacant lower orbital, and a photon is created from the energy. If your material is transparent to that frequency of photon, it will propagate away and voila! light. If not, you get phonons.

a reply to: Bedlam

LED's create phonons? Like in the form of sound or heat?

originally posted by: BASSPLYR
a reply to: Bedlam

LED's create phonons? Like in the form of sound or heat?

In the form of lattice vibrations. Any generic semiconductor junction does this. It's why they get hot. Partly.

Is anyone aware of any theory possibly explaining how quantum tunneling works, specifically in the nuclear fusion field? Or, has there been any attempt to find an easier way to produce fusion (cold fusion doesn't count).

It's almost commonly known that nature doesn't like 'brute force'. So who's to say there isn't a secret to the puzzle we haven't turned up yet? At first thought, it's many times easier to get a neutron past the coulomb barrier than it is a proton. What if we could send a nuetron through the barrier and then turn it into a proton, after it has passed through the barrier?Therefor making it require a lot less energy.

Just a thought, ideas?

originally posted by: IAmTheRumble
Is anyone aware of any theory possibly explaining how quantum tunneling works, specifically in the nuclear fusion field?

I posted an explanation earlier in the thread of how fusion in the sun wouldn't occur without quantum tunneling, so it's happening every day the sun shines. Unfortunately Google changed the way they search forums so it's hard to find old posts now and the ATS search never worked well for me.

This explains why quantum tunneling works and I'm sure it happens in manmade hot fusion reactors too:
Quantum tunneling

I'm interested to see what comes out of this but it will probably be military applications at first:

Compact Fusion

We already have a fusion reactor: the sun. Plenty of energy from the sun strikes the Earth, so I think the trick is to figure out how to use that more efficiently. 80% efficient solar cells for example would help. Current solar cell tech is relatively inefficient but improving, though still nowhere near 80%, in fact you're doing well to get 40% and many installations get half that.

originally posted by: IAmTheRumble
Is anyone aware of any theory possibly explaining how quantum tunneling works, specifically in the nuclear fusion field? Or, has there been any attempt to find an easier way to produce fusion (cold fusion doesn't count).

It's almost commonly known that nature doesn't like 'brute force'. So who's to say there isn't a secret to the puzzle we haven't turned up yet? At first thought, it's many times easier to get a neutron past the coulomb barrier than it is a proton. What if we could send a nuetron through the barrier and then turn it into a proton, after it has passed through the barrier?Therefor making it require a lot less energy.

Just a thought, ideas?

Don't think this would be an effective answer for fusion on earth. Quantum tunnels works for a star it lets protons get close enough together to fuse and make a nucleus of deuterium. Problem is the reason it works for thr sun is the huge amount hydrogen in one place. It turns an event with a very small probability if happening into a common occurrence. On earth wr just can't replicate the shear volume and the number of possible collisions. The only other way ti break coulombs barrier is if we find a way ti cause quantum tunneling taking it from a rare ocxurance to an expected one. But again this may violate the laws if physics thus is sort of a grey area.

Thanks for the replies, I'll take a look at the links.

originally posted by: IAmTheRumble
Thanks for the replies, I'll take a look at the links.

Review the previous link also. I found where I answered this before, and my reply was to you! On page 177, see my reply and the link there which explains more details:

Previous answer explaining fusion in the sun using quantum tunneling

In a nutshell though, you need ~10 billion degrees for fusion without quantum tunneling, while the mere 27 million degrees in the sun's core is adequate with quantum tunneling, though as dragonridr said, we are dealing with statistical distributions rather than precise cutoffs.

What is graviton radiation?

Physics is mostly maths, right? So can one of you smart guys explain what is up with 9?

8*9=72 (7+2=9)
165*9=1485 (1+4+8+5=18 1+8=9)
8756*9=78804 (...=27 2+7=9). Always 9
Why is that so?

Oh is it maybe because of 3? Because 9=3^2 & 3+3+3=9
And 3 a prime number?

a reply to: Peeple

Yes

If the sum of the digits is divisible by 3, the number itself is divisible by 3.

If the sum of the digits is divisible by 9, the number itself is divisible by 9.

nrich.maths.org...

originally posted by: Peeple
Physics is mostly maths, right? So can one of you smart guys explain what is up with 9?

8*9=72 (7+2=9)
165*9=1485 (1+4+8+5=18 1+8=9)
8756*9=78804 (...=27 2+7=9). Always 9
Why is that so?

It's not particularly special to 9, it's a characteristic of base number less 1, which in base 10 happens to be 10-1=9

In base 8 the same thing happens with the base number less 1: (7)

Base 8:
165*7=1463(base 8) =>1+4+6+3= 16 (base 8) => 1+6=7

In base 16 it happens with the base number less 1: (F)

Base 16:
165*F= 14EB(base 16) => 1+4+E+B= 1E (base 16) => 1+E=F (base 16)

Oh is it maybe because of 3?

The reason I think it has nothing to do with 3 is because it works with 7 in base 8. I can't see how 3 has anything to do with it when you look at that.

Not really a physics question though.

What do you think the peak of our technological journey will be? Seeing as though I lack wisdom (you know, cause I'm young and apparently dumb, according to the media). Those with more wisdom, please bring me back to earth. Cause I still believe Lazar...

a reply to: Arbitrageur

originally posted by: greenreflections
thank you.

I take it you replied affirmative to my first question.
would the same apply to photon also?

thanks for avatar tip.
You're welcome for the tip.

I purposely avoided a direct answer to your question about whether the electron will get where you aimed it because you said there's nothing in its way.

That's right. That was the only consideration. If I asked you how would behave free electron in interstellar space, I would ask you straight forward.

In case where single photon is released from photon gun in space, would my wide big, enormous in size detector catch that same single photon or it will arrive as a wave with the most energetic impact being on bulls eye?

I would think that photon released will start to spread wider as it travels and detector reacts on its arrival as the wave, meaning multiple cells of detector register it with most impact at the place of the detector where I aimed it.

What do you think?
Although, I know, you will say that you did not understand any of what I asked. Am I right?)) Just kidding.


In this view I think that photon at the moment of release spreads as a wave. Wave pulse (single photon).
Meaning that pulse is not going to stay confined to the size diameter of photon gun barrel diameter. Pulse as all pulses do, will grow and spread like a 3d equivalent of water flat surface wave does when you drop a stone on it.
Confusion enters, imo, is that detector still registers a photon albeit all detector cells will register same photon. Only the one that hit the detector head on will have slightly different (stronger) readings. It is tha same photon I released from the photon gun after all, right? Only 'flattened', spread its single initial presence over certain area like a water ripple. Momentum still there only photon will be red shifted.
Unless some sort of collapse involved where first cell on detector that reads photon collapses some how entire wave, reducing it to a single instance.

Asking to make sure we are on the same page.



thank you)

hey questions for you guys again.

reading some of Froning's papers, which are fascinating.

can anyone break down for me the differences between SU (1), SU (2) & SU (3) fields.

I'm seeing terms like A Fields and teardrop shaped toroids and my eyes are lighting up and my mind jumping to conclusions.

any help with the SU Maxwell equation related question above so I can get a better grasp of what I'm reading and reel in my wild speculative thoughts and come to a more sober conclusion

originally posted by: Arbitrageur

originally posted by: Peeple
Physics is mostly maths, right? So can one of you smart guys explain what is up with 9?

8*9=72 (7+2=9)
165*9=1485 (1+4+8+5=18 1+8=9)
8756*9=78804 (...=27 2+7=9). Always 9
Why is that so?

It's not particularly special to 9, it's a characteristic of base number less 1, which in base 10 happens to be 10-1=9

In base 8 the same thing happens with the base number less 1: (7)

Base 8:
165*7=1463(base 8) =>1+4+6+3= 16 (base 8) => 1+6=7

In base 16 it happens with the base number less 1: (F)

Base 16:
165*F= 14EB(base 16) => 1+4+E+B= 1E (base 16) => 1+E=F (base 16)

Oh is it maybe because of 3?

The reason I think it has nothing to do with 3 is because it works with 7 in base 8. I can't see how 3 has anything to do with it when you look at that.

Not really a physics question though.

I like this answer.

It also is not limited to simple modulus (essentially remainders and the theory which acts as the 'proof' that validates the use of division).

A similar effect is seen in repeating series of decimals found when dividing by 3,4,9 ect. (the remainders will cycle through numbers like 0.34 then 0.349 then 0.3497 then return to 0.34 and so you can tell how far through a cycle you are. Think of a clock always showing 1-12).

The question was really more aimed toward the mathematical applications of set theory more so than physics.

-FBB

a reply to: Arbitrageur

I know it wasn't physics, but still a big:
Thank You!