What is the Direction of the B Field from Electron Motion?

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Homework Help Overview

The discussion revolves around understanding the direction of the magnetic field (B field) resulting from the motion of an electron, utilizing the right-hand rule. Participants are exploring the implications of charge polarity on the application of this rule.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to apply the right-hand rule to determine the direction of the B field, questioning their interpretations of the rule based on the charge of the electron. There is a focus on clarifying the conventions used in the right-hand rule.

Discussion Status

The discussion is ongoing, with some participants recognizing potential errors in their application of the right-hand rule. There is an acknowledgment of the need to verify conventions and directions used in their reasoning.

Contextual Notes

Participants are discussing the implications of using different conventions for the right-hand rule and how this affects the understanding of the magnetic field direction for a negatively charged particle like an electron.

PhysKid45
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Member advised to use the homework template for posts in the homework sections of PF.
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Hello PF friends.

I know what the answer is, but I do not understand why the answer is.

By the right hand rule I put my thumb west, but pointer up, and the field (middle) points North - BUT it is an electron so the field points South.
I also tried pointing my hand west, curling my fingers up, and my thumb points North - again the electron means the field should be South.

My problem is that the answer is North and I do not know why.
 
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In using the right-hand rule, there are different conventions for what the fingers and thumb represent.

Can you state what convention you are using?
 
For the first one my thumb is the velocity, my pointer is the direction of the force, and my middle is the B field.
For the second version I essentially point my entire hand towards velocity, and curl it in the direction of the force (curl up because the electron moves up), so the thumb is the B field.
 
I believe these directions are incorrect for a positive charge. Double check your textbook or notes.
 
Ok I had my pointer and my middle fingers wrong for the first one, and for the second one my thumb points in the direction of the force and curls in the direction of the B field.

Thanks!
 

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