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# The flaming left hand rule

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1. When we want to show the direction of motion of a particle using the left hand rule which finger do we use???My teacher has totally confused me...
Help plz
2. (Original post by zazy)
When we want to show the direction of motion of a particle using the left hand rule which finger do we use???My teacher has totally confused me...
Help plz
thumb
3. (Original post by zazy)
When we want to show the direction of motion of a particle using the left hand rule which finger do we use???My teacher has totally confused me...
Help plz
thumb = motion direction
first finger - field direction
second finger = current direction
4. (Original post by DazYaYYY)
thumb
that's exactly what i thought..she was saying the 2nd finger!!!Grrrr
5. (Original post by zazy)
that's exactly what i thought..she was saying the 2nd finger!!!Grrrr
haha she's a silly billy then
6. thumb - motion
first finger - field
second finger - current
7. remember that if an electron (or any other negatively charged particle) is going one way then the current going the opposite way
so if an electron is moving like this:
-------->
then the current is in this direction:
<-
i hope i didnt confuse you... its just a common mistake thats worth pointing out imo...
8. MFI - Motion, field, current
9. (Original post by elpaw)
thumb - motion
first finger - field
second finger - current
yeah, i shall teach her that tomorrow.....
10. (Original post by zazy)
that's exactly what i thought..she was saying the 2nd finger!!!Grrrr
as long as the first figer is the current and the thumb is the field, she is correct.
11. (Original post by Mysticmin)
MFI - Motion, field, current
yup thats how i remember it
12. (Original post by S1M)
yup thats how i remember it
If you have to use it in exams do you actually mess about with your hands?
I find it kind of embarassing..
13. (Original post by zazy)
yeah, i shall teach her that tomorrow.....
your gonna teach ur teacher? lol... i used to do that at primary school... well sorta... thats what too much maths tuition at a young age does to ya
14. (Original post by zazy)
If you have to use it in exams do you actually mess about with your hands?
I find it kind of embarassing..
lol... dont worry about it... everybody is going to be worried about their own paper to be noticing what you are doing...
15. (Original post by S1M)
lol... dont worry about it... everybody is going to be worried about their own paper to be noticing what you are doing...
From everybody do you mean the other fellow classmate apart from me that will be sitting the paper?
LOl...
16. (Original post by zazy)
From everybody do you mean the other fellow classmate apart from me that will be sitting the paper?
LOl...
lol... sorry didn't know that... in my school load of people do physics... well just be embarassed then... if it gets u the marks its worth it
17. (Original post by S1M)
lol... sorry didn't know that... in my school load of people do physics... well just be embarassed then... if it gets u the marks its worth it
I am agreeing there, my old history teacher sat and laughed silently when our entire physics class did that all at once in an exam
18. lol. I'm the only one at my school doing nuclear & particle physics, everyone else is doing cosmology (my class is at a different school due to timetable clashes, it's a consortium, don'tcha know...). So I'm probably gonna be sitting there alone working out the direction of a proton while they're off describing the life cycles of stars...
19. haha i remember doing the left hand rule and our physics teacher got really excited about it! he used to rise to his tiptoes on the stressed bits of the words: ffffffffffffffirst ffffffffffffinger = fffffffffield
seCond finger = Current
thummmmmmmmb = mmmmmotion
and he had a broad yorkshire accent so the mmmooootion got him really excited. bless him! he then retired and made his attic into a weather station.
20. I think im the only one that remembers it this way, but we were taught FBI
F for Force ,B magnetic field (think magnetic flux density) and I for current, its helps me anyway!

Updated: June 27, 2004
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