Understanding Left/Right Hand Rule and Finding North/South in Currents

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Discussion Overview

The discussion revolves around the application of the left-hand and right-hand rules in electromagnetism, particularly in relation to electric forces and magnetic fields. Participants also explore how to identify the North and South ends in the context of electric currents and coils.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about the application of the left-hand and right-hand rules, particularly regarding which fingers correspond to different physical quantities.
  • Another participant asserts that right-hand rules are the standard for vector directions, noting that left-hand rules are only applicable in specific materials with negative permittivity and permeability.
  • A participant clarifies that current itself does not have a North or South end, as it consists of electrons, which behave as monopoles.
  • One participant revises their question, indicating they were thinking of a coil in a circuit when asking about North and South ends.
  • A participant attempts to explain the right-hand rule using a visual description involving the orientation of the hand and the direction of current flow, suggesting that magnetic flux flows in a specific direction related to the configuration of the coil.
  • Another participant references educational sources that use "electron flow" terminology, suggesting that this may lead to the use of left-hand rules in certain contexts.

Areas of Agreement / Disagreement

Participants express differing views on the use of left-hand versus right-hand rules, with some asserting the predominance of right-hand rules while others reference contexts where left-hand rules may apply. The discussion on identifying North and South ends remains unresolved, with varying interpretations of current flow.

Contextual Notes

There is ambiguity regarding the definitions of current and its directional properties, as well as the applicability of left-hand and right-hand rules in different contexts. The discussion reflects a range of understandings and assumptions about these concepts.

Soph
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Throughout the electric force/field and magnetism unit, there's always a rule that involved using the left hand and the right hand. I'm a bit confused on how to apply the rules because of the units are applied to different fingers. If someone could give me an explanation on it, that'd be great.

Another question: How do you find which end is North and which end is South in a current?
 
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To the best of my recollection, all vector rules and directions of note require that only right-hand rules are used. The only time I have seen left-hand rules used are in left-handed materials where both the permittivity and permeability are negative. These are not encountered naturally.

Current does not have a north or south end. Current is made up of electrons, point charges, that act as monopoles, they do not have two poles to reference as north and south.
 
After looking at it for a while, I kind of understood the concepts.

My apologies for the second question. I was picturing a coil in a circuit when I typed this.
 
Hi Soph

Thanks for giving me the opportunity to try and explain this. I am only a novice at electromagetics, but I have just recently gone over the same ground of questioning that you have raised in this question ... so here we go... can I do this??

Say your right hand is out in front of you with palm up ...- thumb out to the right ... -and your fingers curled up and back towards you. Say there is a horizontal conductor sitting in that right palm of your hand with conventional current (opposite to electron flow) flowing from left to right. That means you would draw a plus sign on the left of this conductor and draw a negative sign on the right of this conductor ... right ? Now here is the thing - the FLUX will flow in the direction of your curled fingers. And notice this also: - in a coil configuration the FLUX flows from the NORTH towards the SOUTH pole on the outside of the coil and from South towards the North on the inside of the coil.

I can understand this sounds complicated. This is where a picture would come in handy. It is hard to explain this in words.

Anyway thanks for giving me a try at it.o:)
 
Thanks Leon. I've been touching up on that subject, and I had some doubts over that, but I understand it better now.
 
A few sources, one such example is the New York State Regents Physics curriculum, refer to "electron flow" in all cases, and never refer to conventional current, therefore the magnetism unit has left hand rules instead of right hand rules.
 

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