Magnetic flux lines: Left-hand or Right-hand rule?

In Vol. I Chap. 14 under Electromagnetism, it states that "A simple method of showing this relationship [that the magnetic field produced by an electric current is always oriented perpendicular to the direction of flow] is called the left-hand rule".

But in my physics text and my basic circuit theory text states it as the right-hand rule.

Which one is it?

Is is right-hand for conventional current flow and left-hand for electron flow?

 

Right. It explicitly states that the thumb is in the direction of electron flow. This means that it would be opposite for the direction of conventional current flow. While it is strictly correct, I disagree with ever using a left-hand concept with any of this. Everything else in classical physics uses right-hand rules. Let's keep it consistent.

 

This is a serious piece of misinformation in the e-book - yes it is the right-hand rule, or more accurately is represented in these terms by virtue of the solution to Biot-Savart Law on a current carrying conductor. The left-hand rule refers to trust on a current carrying conductor in the presence of a field.

Dave

 

Would it do any good to have two figures: one for conventional current flow emphasizing the right hand rule and another for electron flow refering to using the left hand without actualling calling it the left-hand rule?

 

Certainly, a diagram is worth a thousand words. The two examples side-by-side may well clear up the concept for many folk.

 

I am of the opinion that in the context of this article that only the right-hand rule (cupped-finger = magnetic-field, thumb = conventional current flow) is important - it is the most widely used context. Whilst I agree with thingmaker3 that a picture does paint a thousand words and that this may dispel some of the confusion on this, this episode has illustrated that the opposite may very well be true, that is that there is a risk of confusion when we introduce left and right-hand rules in the same discussion.

A further point I would make is that we have enough problems clearing up confusion about conventional Vs electron current flow, without adding left-hand-right-hand rules in there.

Just my 2 pence on this.

Dave

 

Yes, the cost of living of more than it used to be here too Bill!

Whilst I personally am more happy with electron flow (coming form a semiconductors background) I feel the conflict with using the left-hand rule in this case with electron current flow is that it goes against the convention on this in other standard texts on this subject (Seraway and Beicher spring to mind) who use the right-hand rule with conventional current flow. In essence the current diagram is correct for electron current flow, but this is not consistent with other texts that the reader may be accustomed to. The question is do we enforce one convention and stick to it rigidly, or do we aim to stick with convention for the clarity of the reader and pint out the differences/alternatives where appropriate?

Dave

 

I just came across a good FSU site with right/left hand information - http://www.magnet.fsu.edu/education/tutorials/java/handrules/index.html.