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Physics/Flemings Left Hand Rule vs Right Hand Palm Rule


Left Hand Rule
Left Hand Rule  
Right Hand Rule
Right Hand Rule  
QUESTION: I am really confused about which method to use for finding direction of magnetic force experienced by a charged particle , because they give different results . In the LHR pic , if the direction of magnetic field is downwards (-ve y-axis) , & that of current is straight , we get direction of force according to LHR , along +ve X-axis. However according to RHR , when the thumb points in the direction of current i.e straight , as in case of LHR , & fingers in the direction of magnetic field ,we get force along -ve X-axis i.e opposite to that of LHR .So am i going wrong somewhere or are these rules not same in all cases.

ANSWER: I've never heard of a left hand rule before.  That's a new one on me, but the only real effect is to switch the order of the input variables so it doesn't matter.  Your pictures also appear to be mirrored.  Stick with the RHR, there really is no left hand rule...just the right hand rule done in the proper order.  The second picture only looks wrong because if that's your right hand you've flipped the image...same reason the first picture looks right but wouldn't be if that were really your left hand.

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QUESTION: No , actually Ist diagram is recommended on my reference book , but i find it inaccurate and hard to do . The first technique is Fleming's Left Hand Rule , which is also used for finding the direction of magnetic force due to magnetic field.Here is the statement for Left hand rule given in my book, "IF we stretch the 1st finger , the central finger & the thumb of left hand mutually perpendicular to each other such that the first finger points to the direction of magnetic field, the central finger points to the direction of electric current(motion of positive charge), then the thumb represents the direction of force experienced by the charged particle" . And just for clarification , i took those photos with my webcam and they are my left and right hands respectively and i did not do any mirror or anything like that and thanks for your reply.

It's saying the same thing as I said.  Switch the order of the first and second finger and you switch the hand.  There's no difference.  And the way the photos present is indeed opposite to what you said, there's something going wrong there.  But my recommendation is to just stick with your standard right hand rules.  Much easier.


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Dr. Stephen O. Nelson


I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.


I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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