I was told that Ohm's Law of resistance is wrong?

In summary, the conversation includes discussions about the validity of using Boltzmann's equation in solid state physics and the role of the Drude model in understanding conductivity. It also touches on the topic of quantum electrodynamics and recommended textbooks for further reading. The possibility of using the Kubo model to explain the Kondo effect is also mentioned.
  • #1
stunner5000pt
1,461
2
Is that true?

Becuase like my prof said that the resistivity of an object according to ohms law has nothing to do with certain factors when in reality it does such as current and electric field (i think)

What is this field of QM called? Is it Quantum Electrodynamics?

Can you suggest textbooks or books that would be a good read ?

Note : I'm only in the second year of university - but i'd like to start this sometime!
 
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  • #2
stunner5000pt said:
Is that true?

Becuase like my prof said that the resistivity of an object according to ohms law has nothing to do with certain factors when in reality it does such as current and electric field (i think)

What is this field of QM called? Is it Quantum Electrodynamics?

Can you suggest textbooks or books that would be a good read ?

Note : I'm only in the second year of university - but i'd like to start this sometime!

Read this thread...

https://www.physicsforums.com/showthread.php?t=51204

Zz.
 
  • #3
So then the correction for Ohm's law is given by Drude's Law??
 
  • #4
stunner5000pt said:
So then the correction for Ohm's law is given by Drude's Law??

No, the Drude model is the derivation of Ohm's law... But the Drude model is an over-simplication of the description of conduction electron, where these electron are thought to be "free" electron gas.

You may want to consider reading a solid state physics text if you are that keen on knowing this. I didn't recommend this before because you're only ... what... in your 2nd year?

Zz.
 
  • #5
In the second year he should have serious trouble looking into transport phenomena in solids.As this chapter of solid state physics deals with Boltzmann equation applied to movement of free (electric) charge carries in a crystal,he should be knowing many things,like non-equilibrium statistical physics (kinetic/Boltzmann's equation approach) and fundamentals of solid state physics...I trhink that's too much to ask to a second year student.In my country,solid state is taught in the 3rd year.In parallel with QM and SP.
 
  • #6
dextercioby said:
In the second year he should have serious trouble looking into transport phenomena in solids.As this chapter of solid state physics deals with Boltzmann equation applied to movement of free (electric) charge carries in a crystal,he should be knowing many things,like non-equilibrium statistical physics (kinetic/Boltzmann's equation approach) and fundamentals of solid state physics...I trhink that's too much to ask to a second year student.In my country,solid state is taught in the 3rd year.In parallel with QM and SP.

I don't think one needs to get into the Boltzmann transport equation to understand the Drude model. That is usually the first thing one sees in the very first chapter of, let's say, Ashcroft and Mermin text. I'm not saying he can understand even the Drude model with just a 2nd year education.

However, to understand why even the Drude model itself isn't entirely correct would certainly require understanding the Boltzmann equation and more QM than one has at that level. Interestingly enough, the Boltzmann transport equation itself is highly classical (or maybe even just semi-classical). One needs to go to the Kubo model to get to the QM version of the transport problem. This is fine and dandy, except that the Kubo model is a pain-in-the-ass to solve. This is why the Boltzmann equation is still what we fall back on to very often.

Zz.
 
  • #7
ZapperZ said:
I don't think one needs to get into the Boltzmann transport equation to understand the Drude model.
It's pretty intuitive,yes,you're right.

ZapperZ said:
That is usually the first thing one sees in the very first chapter of, let's say, Ashcroft and Mermin text. I'm not saying he can understand even the Drude model with just a 2nd year education.

Perhaps.Anyway,he should know better what he does know and what he doesn't.


ZapperZ said:
However, to understand why even the Drude model itself isn't entirely correct would certainly require understanding the Boltzmann equation and more QM than one has at that level. Interestingly enough, the Boltzmann transport equation itself is highly classical (or maybe even just semi-classical). One needs to go to the Kubo model to get to the QM version of the transport problem.

Let's not get into technical terms here.There's a huge distance from Drude to Kubo.


ZapperZ said:
This is fine and dandy, except that the Kubo model is a pain-in-the-ass to solve. This is why the Boltzmann equation is still what we fall back on to very often.
Zz.

Yes it's the Boltzmann's equation that gives you the 2nd principle in Clausius formulation,but it's the CLASICAL theory of linear responses developed by Kubo which justifies the linear thermodynamics of irreversible processes developed by Onsager in 1931.So far,i haven't seen any relevant application of the QM version of Kubo's theory,or maybe i haven't read enough on the subject.That should be it...
:tongue2:
 
  • #8
I got another question on the validity of using Boltzmann'e equation wrt to solid-state physics...I'll post in a separate thread.
 
  • #9
dextercioby said:
Yes it's the Boltzmann's equation that gives you the 2nd principle in Clausius formulation,but it's the CLASICAL theory of linear responses developed by Kubo which justifies the linear thermodynamics of irreversible processes developed by Onsager in 1931.So far,i haven't seen any relevant application of the QM version of Kubo's theory,or maybe i haven't read enough on the subject.That should be it...
:tongue2:

It has been a while since I dealt with this, and someone else (Dr. Transport?) can correct me if I'm wrong, but I think Mahan dealt with the Kubo model in his Many-Particle Physics text. And unless I am mistaken, the Kondo effect is one of the phenomena that can be explained starting with the Kubo formulation. The spin-flip between the conducting electron and the magnetic background cannot be included using Boltzmann transport equation.

Zz.
 

1. What is Ohm's Law of resistance?

Ohm's Law of resistance is a fundamental law in physics that states the relationship between voltage, current, and resistance in an electrical circuit. It states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor.

2. Is Ohm's Law of resistance always accurate?

Yes, Ohm's Law of resistance is accurate under certain conditions. It is based on the assumption that the temperature, material, and physical properties of the conductor remain constant. If any of these factors change, then the law may not hold true.

3. Can Ohm's Law of resistance be disproven?

No, Ohm's Law of resistance has been extensively tested and verified through experiments. It has been proven to be accurate in most cases and is widely used in electrical engineering and physics.

4. Why do some people say Ohm's Law of resistance is wrong?

Some people may say that Ohm's Law of resistance is wrong because they are misinterpreting the law or using it in situations where it does not apply. It is important to understand the limitations and conditions under which the law holds true.

5. Are there any exceptions to Ohm's Law of resistance?

Yes, there are some materials and circuits where Ohm's Law of resistance does not hold true. These include non-ohmic materials like diodes and transistors, as well as circuits with complex components like capacitors and inductors. In these cases, more advanced laws and equations are used to describe the relationship between voltage, current, and resistance.

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