AC vs DC: Exploring the Effects of Earth's Magnetic Field on Currents

[mikee]

Homework Statement

Hello i just have an interesting question, and was wondering if my answer to it had any validity.
Ok so i did an experiment The Current balance experiment(for everyone not familiar with it, you can google it and get all the info you want) to try and estimate mu naught. Anyways AC current was used in the experiment so transformers could be used to adjust the voltage applied to the circuit. So the question was why else was AC current used rather than DC. My answer to this question is, could this be due to the fact that the Earth has a magnetic field that will effect the experiment because the of the hall affect. Which is when charge carriers of a current carrying conductor experience a sideways Lorentz force due to Earth's magnetic field which results in a charge separation in a direction perpendicular to the current and to the magnetic field. So will this affect DC current because it only flows in one direction, but since AC flows in both directions will it somehow cancel out the Lorentz force?

Homework Equations

The Attempt at a Solution

 

[berkeman]

Homework Statement

Hello i just have an interesting question, and was wondering if my answer to it had any validity.
Ok so i did an experiment The Current balance experiment(for everyone not familiar with it, you can google it and get all the info you want) to try and estimate mu naught. Anyways AC current was used in the experiment so transformers could be used to adjust the voltage applied to the circuit. So the question was why else was AC current used rather than DC. My answer to this question is, could this be due to the fact that the Earth has a magnetic field that will effect the experiment because the of the hall affect. Which is when charge carriers of a current carrying conductor experience a sideways Lorentz force due to Earth's magnetic field which results in a charge separation in a direction perpendicular to the current and to the magnetic field. So will this affect DC current because it only flows in one direction, but since AC flows in both directions will it somehow cancel out the Lorentz force?

Homework Equations

The Attempt at a Solution

Please do not tell us to "Google it" to find the background and context of your question. That is a bit insulting, and a waste of our time.

Anyways AC current was used in the experiment so transformers could be used to adjust the voltage applied to the circuit. So the question was why else was AC current used

I think your point about the Earth's DC magnetic field may be valid, but without more info on the experiment that you conducted, it's hard to give you useful feedback...

 

[mikee]

Ok i didnt mean to insult anyone, i just thought anyone who could answer the question would be familiar with the experiment and disregard that comment. Anyways In this experiment we used a current balance in which the upper conductor is free to pivot
on knife edges. The upper conductor is balanced so that the wires are a small distance apart. The conductors are wired in series to carry the same current but in opposite directions, so that the wires rather repel than attract. So we are to measure the displacement of the two parallel conductors where as stated above only the top wire is able to move

 

[berkeman]

Ok i didnt mean to insult anyone, i just thought anyone who could answer the question would be familiar with the experiment and disregard that comment. Anyways In this experiment we used a current balance in which the upper conductor is free to pivot
on knife edges. The upper conductor is balanced so that the wires are a small distance apart. The conductors are wired in series to carry the same current but in opposite directions, so that the wires rather repel than attract. So we are to measure the displacement of the two parallel conductors where as stated above only the top wire is able to move

Is one of these images applicable (yes, I couldn't take it, I Googled it):

http://www.google.com/images?rlz=1T...ent&um=1&ie=UTF-8&source=og&sa=N&hl=en&tab=wi

From your description so far, I'm not seeing where a DC B field from the Earth would be a factor. Maybe the AC component comes in for signal-to-noise ratio improvement? Are you familiar with why that can help SNR?

 

[mikee]

Yes the second image is applicable. Where T and H are the parallel conductors where the current will run to make them repel each other. And I am not exactly sure why the AC component would help? I would think because it oscillates back and forth it would be harder to filter the noise out?