Physical Science 6.8b - Magnetic Force on Moving Charge

From the Physical Science course by Derek Owens. An explanation of the force exerted by a magnetic field on a moving charge. Distance learning classes are available at http://www.derekowens.com

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Education

Tags:

• Physical Science
• Science
• Physics
• magnet
• magnets
• magnetic
• magnetic force
• moving charge
• right hand rule
• Derek Owens
• distance learning

[freerider10000]

Hi, I'm just wondering why you use the Right hand rule to determine the direction of a magnetic force instead of Flemings Left hand motor rule?

From my understanding the Flemings Left hand motor rule says the First finger points along the Field direction (From N to S). The seCond finger is the Current direction (from + to -) and then the Thumb gives the direction of the Thrust (or the Force).

(Note I'm from the UK and only use Right hand Rule for generators and stick to conventional current)

[derekowens]

@freerider10000 The actual direction is a source of constant confusion because there are two ways to think of it. If you imagine the current to be positive charge flowing, what we call conventional current, then you use the right hand rule. If you imagine it to be negative charge flowing in the other direction, what we call electron flow, then you use the left hand rule. Positive charge flowing in one direction is mathematically equivalent to negative charge flowing in the other direction.

[12345Anee]

@derekowens

but Sir, that guy is asking about Flemings Left hand motor rule.....!!!!

even i m also wondering why you use the Right hand rule to determine the direction of a magnetic force instead of Flemings Left hand motor rule?

[derekowens]

@12345Anee I think I need to make a video on Flemings motor rule. I have to find some free time first, and that's pretty scarce these days...

[AceFrolic720]

@derekowens but in this video... using the LHR for the same moving positive charge,

I get a downward force.

and you said, that the LHR is only applicable to the flow of electrons.

=S

[derekowens]

@AceFrolic720 If you are thinking of the positive charge flowing, then you should use the Right Hand Rule. Positive charge flowing one way is mathematically the same as negative charge flowing the opposite way. You should get the same result for your force vector either way.

[balochan1]

are the yellow lines representing the force or the magnetic field?

[viviannaipp]

can i use the FBI rule for this?

[mephatboi]

@mephatboi nvm, u answered it in the next video (i.e. fingers must curl in the direction of the south pole)! thx...

[mephatboi]

how did u know to point ur thumb downwards (not upwards) in the 1st instance of the moving particle and upwards (not downwards) when it traveled in the opposite direction?

[DisturbedV7]

I dont understand the bit about the magnet and using the right hand rule, are your fingers not wrapped around when the actual field lines are straight?

[naruto2710]

i'm confused, do all charged particles hav a magnetic field around them; so in your last example, the charge q. so are there 2 magnetic fields interacting in that situation. what i'm trying to understand is determining the force etc when we have an interaction of magnetic fields produced by a permanent magnet and an electromagnet (i.e. from current in wire)