Left and Right hand rule!!??!! (1 Viewer)

[lost1]

Ok this things starting to bug me...anyways from my knowledge this is how you use left hand rule for negative charged particle (electron)

That is the thumb directs the motion of the electron and the palm directs the force that is applied on to the electron correct? (please correct me if im wrong)

But what is the difference between the two....what i mean is how do i know which direction is the 'force' and which direction is the motion?

For example i have to choose which direction the current flows when the coil is turned as shown in this example:

So i get aswer A...But if you use the 'grip rule' (where you grip it so that the fingers direct against the magnetic field) the answer is B!!!


Can someone please help me out on this confusion???

P.S sorry for the dodgy drawing but its better than i can explain it...

thanks

 

[dolbinau]

Use the grip rule only for solenoids.

But I'm not sure what you mean : Regarding force/motion. The force on both sides of the coil will be equal and opposite, hence torque which creates the motion.

I'm not really sure what you are asking, sorry!

 

[lionking1191]

electrons is negative. the rule is for positive currents. so just use the rule and reverse whatever you get if you get electrons

 

[obimoshman1234]

left hand is for electrons
right hand is for protons

however for ur rule u havent outlined the direction of the field with ur hand need to do that.

dolb wrong rule used more places than just solenoids. i mean how else u suppose to work out direction of force on current carrying wire??????

i tend to use three fingers for it assigning each to one thing

Thumb: points in direction of charge or current
INdex: points in direction of magnetic field lines so into or out of page
rude finger(yes i dont know whats it probably called) will be at 90 degrees inward to index finger in direction of force

like that

 

[dolbinau]

dolb wrong rule used more places than just solenoids. i mean how else u suppose to work out direction of force on current carrying wire??????

Can you give a situation? I guess it helps with parallel wires but don't you use the right hand palm rule for force on a current carrying wire in an external field?

 

[lost1]

left hand is for electrons
however for ur rule u havent outlined the direction of the field with ur hand need to do that.

hhmmm....

so basically for mine:

-the fingers point in magnetic field direction (North to South)

-Thumb point towards current flow(or with left hand the flow of electron) and the

-palm of the hand (or more specifically, perpendicular to the palm pointing away form it) is the direction of the Force

...so yeh...hmmm...so the answer to the question(example) i drew up is B??

 

[obimoshman1234]

ok for ur uestion it is b yes because ur palm should be facing upwards if current is flowing anticlowise with field going from left to right



and dolb thats what i meant it is used for force between two wires and i dont think anything else but still not just solenoid

 

[Shoom]

What dot point is this hand rule business related to from motors and generators.

 

[obimoshman1234]

lol dont know but i have seen it in my notes somewhere and on past hsc papers so need to know it obviously

 

[Shoom]

Damn none of the nothin the resource centre have anything about this hand stuff.

Are yousure this isnt for idea o implemenntion beccause we talk about protons and electrons their.


Sorry about spelling, wireless keyboard is getting annoying.

 

[lost1]

yeh its certainly part of motors and generators...you use these rules to figure the direction of current and forces etc in motors and generators

 

[dolbinau]

Damn none of the nothin the resource centre have anything about this hand stuff.

We aren't told to use the right hand palm rule, we have to solve problems relating to torque/induction etc.. and the way we do this is with the right hand palm rule. It's not a scientific 'proof' or anything (so never quote it in the exam), it's just an aid. If that makes sense. Same with right hand grip rule. (it's just a method it's not an actual physics law or anything)

 

[Shoom]

Thankyou, sorry im just starting the HSC.

COuld you please tell me which dot point this is specifically related to

and in motors and generators do we use conventional current or electron flow?

 

[lost1]

You always use conventional current unless the question specifically mentions electron flow

 

[henry08]

I only use the right-hand push rule. Just reverse the direction of the thumb for negative charges.