# Can Hydrogen have a DC Circuit?

1. Aug 30, 2004

### kichigai

[SOLVED] Can Hydrogen have a DC Circuit?

I'm thinking of the hydrogen atom like it might be a DC type of electrical circuit, just for fun, but I am not sure what values to use for a couple of simple equations. Can somebody help me out?

The equation is V=I*R

I found an impedance value, Z, in NIST's list of constants and stuff, a factor they call "Characteristic Impedance of the Vacuum". That Z value = 376.73 ohms. Can I use that as R?

I know the BE for the H 1s electron is 13.06 eV, and it looks like I can use it for V, but I'm not sure since it has units of "eV". Can I use it for "V" as it is or do I have to change it or do something else?

Maybe I can use the charge, Q, of the electron and calculate "V" from capcitance "C" using C = Q/V, but I have the same units problem.

Thanks for any help!
Hey, maybe I can use this for a science project!

2. Aug 30, 2004

### chroot

Staff Emeritus
The electron-volt is a unit of energy. The volt is a unit of electrical potential. The electron volt is the amount of kinetic energy gained by electron when moved through a potential of one volt. They are not interchangeable.

Besides, the entire premise of what you're trying to do is speculative. There is no "DC circuit" inside a hydrogen atom in any respect whatsoever.

- Warren

3. Aug 30, 2004

### Gonzolo

The number 1 problem you won't be able to get around is the fact that a hydrogen atom doesn't use energy over time, while a DC circuit needs some continuously.

4. Aug 30, 2004

### ZapperZ

Staff Emeritus
The number 2 problem is that Ohm's Law is based on the Drude model of FREE electron gas in a conductor. How is this anywhere similar to a hydrogen atom?

Zz.

5. Aug 30, 2004

### kichigai

Bummer! I was kinda hoping that I could get some kinda number even though it might not be a real number. Are you guys really sure that I can't get even a Voltage number?

6. Aug 30, 2004

### ZapperZ

Staff Emeritus
Look, the reason why physics is called PHYSICS and not MATHEMATICS is because the quantity and numbers we obtain have PHYSICAL MEANINGS. You can crank out any numbers and equations that you want out of your imagination, but it doesn't mean any of these have any physical significance. If you can't show any physical significance of a number that you crank out, or why such model is valid, then any result that you arrive at is meaningless.

Zz.

7. Aug 31, 2004

### kichigai

I understand. You said when an electron moves through a potential of one volt it then has one electron volt of energy. Right?

When a free electron flies toward a free proton, does the electron develop potential as it flies closer and closer to the proton? If so do you have an idea or a number for the potential when the electron is 0.53 Ang away from the proton? Can I think of that as a short burst of electrical current?
Thanks!

8. Aug 31, 2004

### what_are_electrons

Is Ohm's law involved in controlling, understanding or predicting how free electrons fly around a synchrotron loop?

If so, then it seems that the electron, in its particle form, imitates the electron beam in the synchrotron because that one electron flies around the proton of hydrogen such that the center of the synchrotron serves as the proton. What do you think of this perspective?

9. Aug 31, 2004

### chroot

Staff Emeritus
The beam path in a synchrotron is nothing at all like an electron in an orbital in an atom. Electrons do not "orbit" nuclei. Atoms are quantum-mechanical systems, while synchrotrons are not.

- Warren

10. Aug 31, 2004

### marlon

yet QM-processes occur in synchrotrons

regards
marlon

11. Aug 31, 2004

### ZapperZ

Staff Emeritus
While that is technically true, it isn't what is used in the majority of the dynamical description of a synchrotron. Classical E&M is alive and well in terms of beam physics, and the same can be said for describing the electron beam in a synchrotron. So Chroot is correct in saying that a synchrotron is a "classical" system.

Zz.

12. Aug 31, 2004

### kichigai

Did I get skipped?
I liked the answer given to What are electrons, but didn't see anything about my question. Can you give me a hint? Thanks!

13. Aug 31, 2004

### what_are_electrons

The nucleus is understood to have a shell structure with orbits that imitate the shell structure of the electrons. Are the neutrons and protons delocalized like the electron clouds and as a result do not "orbit" or move around inside the nucleus in a structured manner? This implies that the nucleus should also be a cloud like system. This arrangement would suggest that there is there is a great deal of spherical symmetry within the nucleus.

What is it that tells us that electrons do not orbit?

Last edited by a moderator: Aug 31, 2004
14. Aug 31, 2004

### ZapperZ

Staff Emeritus
I am guessing that you either haven't studied E&M much, or if you did, you haven't fully understood it yet.

1. An electron going through a potential difference of X Volts will GAIN an kinetic energy equal to X eV.

2. The proton in "electron develop potential as it flies closer and closer to the proton" is IRRELEVANT. All that proton does is to be the SOURCE of the electrostatic potential field that the electron sees, the SAME potential that is in #1. When you have the potential field due to that proton, then you can ignore that proton and simply deal with the resulting field. This field is what is causing ALL the relevant interaction on that electron.

3. For a finite, bound charge, by definition, the zero value of the electrostatic potential is at infinity from the source charge. So all the electrostatic potential values are "calibrated" from this zero value. You can then calculate ALL the necessary energy gain or loss by that electron at ALL locations to your heart's content once you know this and #2.

4. Useful websites such as Hyperphysics has the electrostatic potential field for point and spherical sources.

Zz.

15. Aug 31, 2004

### Locrian

How about the fact that, in its rest state, the electron has no angular momentum? Seems hard to describe it as an "orbit" with no angular momentum...

16. Aug 31, 2004

### marlon

Indeed, but relativistic and QM-notions are also to be taken into account when looking for a complete description of the synchrotron and what it does.

regards
marlon

17. Aug 31, 2004

### ZapperZ

Staff Emeritus
Relativistic, yes. It takes no effort to get a bunch of electrons to the relativistic regime. But where exactly would "QM-notions" come in?

Zz.

18. Aug 31, 2004

### marlon

Well, when an incident particle at high speed interacts with an atomic nucleus, don't we need QM (or QFT) in order to describe what happens. I mean fission and fusion are processes where the QM-regime can be applied, not ?

Maybe I am looking at this to much in terms of the theory-aspect. I am thinking of processes like fission described in terms of the strong-force mediating pions intechanged between hadrons.

Please, let me know if I am exagerating...

regards
marlon

19. Aug 31, 2004

### ZapperZ

Staff Emeritus
Humm... I could have sworn that we are talking about a "synchrotron" here.

A synchrotron is an electron storage ring. The APS here at Argonne has a ring with a circumference of almost 3/4 of a mile. In it, bunches of electrons just go round and round and round and round..... There are no collisions with anything. In fact, collision is BAD! We don't want them since it will degrades the beam quality.

It is this that I insisted that classical physics is alive and well, and that there are no QM effects that are significant enough that QM description has to be used.

Zz.

20. Aug 31, 2004

### marlon

Ok, humm, in the case of the synchrotron, you are right. I know this what we were initially talking about.

The remarks I made concerning QM and special relativity where made as a remark to high-energy-collisions and more generally high-energy-physiscs.

Sorry, i must have confused You.

regards
marlon

21. Sep 1, 2004

### what_are_electrons

Never heard of anyone actually bringing an electron to rest, so I wonder if that is a relevant point since particles are never at rest. At rest seems to be a useful reference point, that does not however exist sorta like an imaginary number. Yes?

22. Sep 1, 2004

### what_are_electrons

Are you saying that Ohm's law does not apply to the operation of the Synchrotron beam?

23. Sep 1, 2004

### Locrian

Rest state, as in not excited. More specifically, the lowest electron energy level around the hydrogen atom. The electron has a probability distribution around the nucleus, but has no angular momentum. This is an obvious reason that calling it an "orbit" is a really bad analogy.

24. Sep 3, 2004

### axawire

hydrogen atom....ohms law... well ohms law is really for macro scale objects for a start, the resistance is not allowed to varie on the amount of current or voltage applied... what could you image for R in a hydrogen atom?.... well anyway....

from past experience just telling someone its not a valid question doesnt seem to solve there problem and get pretty upset, so...

As the classical idea of an electron "orbiting" a hydrogen atom isnt correct... SO IS THE FOLLOWING... but if you really wanted to float your boat and it makes you happy... i guess you could work out how fast an electron would have to be travelling to actually orbit a proton at a certain radius... from balancing F=mv^2/r and F=kq1q2/r^2 and then going by what the definition of electron current, number of electrons per second through a conductor... but in this case i suppose you would use the cross sectional area of an electron... but this electron in the classical sense is in perpetual motion... so as soon as you tried to make it do work you would loose your current...

also looking at it another way... you have a proton... a positive charge source... performing pd = - integral(E.dl) (where E, dl are vectors and the . is the dot product and the pd is the potential difference (measured in Volts)) doing this on any closed loop (circuit) around the proton the p.d will be found to be zero. so no p.d no current around the loop.

but given that DC implies a single direction for the current and
from QM's uncertainty principle you cant get a DC
because you would not get the same direction for the electron every time you took a measurement.

25. Sep 3, 2004

### kichigai

I was originally talking about the flow of "pseudo current" between the proton and the electron because I read somewhere that "virtual electrons and photons" are shared (exchanged?) through the empty space in between the proton and the electron. The voltage difference is the difference in voltage difference between the proton and the electron. I understand that electrons flows from negative to positive and thought the "virtual" electrons would do that. It seems like the virtual photons would be the return circuit. So, I'm trying to describe a flow of current from the electron to the proton and back. Can you guys tell me if that is OK or not?

Thanks! I really appreciate your advice above. I'll do some study and see what stuff falls out.