
#1
Oct909, 05:23 PM

P: 107

1. The problem statement, all variables and given/known data
I am really confused, and why magnetic field is created in a current, electron or the wire create the field? ty, any help would be appreciated 2. Relevant equations 3. The attempt at a solution 



#2
Oct909, 05:51 PM

P: 1,133

You can visualize your standard 3 dimensions with one dimension as leftright, one as updown, and the other as forwardbackward. Displaying 3 dimensions on a page is timeconsuming, so they use "into the page" for forward and "out of the page" for backward.
I can't really say why something happens, but an electric field that changes over time can induce a magnetic field. In a current, you have a net movement of charges, so the electric field of a charge at some point is changing due to that charge moving farther away. 



#3
Oct909, 06:00 PM

P: 107

but where is the page in magnetic field? between two magnet?




#4
Oct909, 06:08 PM

P: 107

what is out of the page and into the page mean in magentic field?
also can you teachme how to do this question,
an electron is traveling north through a magnetic field that is vertically upward. in what direction will the magnetic force be? for this question , if i use left hand rule, how is it possible to move the thumb and and finger both north(upward?) ty! 



#5
Oct909, 06:13 PM

Mentor
P: 39,589

The correct equation to use is the Lorentz force equation. Can you show us that equation? Are you familiar with how the vector cross product in that equation works? 



#6
Oct909, 06:26 PM

P: 107

but my teacher said we use left hand rule, in Calgary
i am not sure, in the textbook, it said use left hand for electron, and right hand for positive this one ? 



#7
Oct909, 06:32 PM

Mentor
P: 39,589

F = qv X B Where F is the resultant vector force, q is the charge, v is the vector velocity, and B is the vector magnetic field. q has a + sign if it is positive charge, and a  sign if it has negative charge. That changes the direction of the first vector in the cross product, which is why you use the RHR always, and get the correct answer for both negative and positive charges. Have you learned the vector cross product yet? 



#8
Oct909, 06:36 PM

P: 107

no , i guess, i am new to magnetic and we just finish electric field
Do i need this F = qv X B to answer the question? 



#9
Oct909, 06:42 PM

Mentor
P: 39,589

Using the right hand rule, a crossed into b gives c
http://en.wikipedia.org/wiki/Right_hand_rule Which is what you are doing with the Lorentz force equation. qv crossed into B gives you the force F. If the sign on the charge is negative, that turns the direction of the qv vector around, so you still use the RHR but with the qv vector pointing the opposite way. 



#10
Oct909, 06:45 PM

Emeritus
Sci Advisor
PF Gold
P: 16,101





#11
Oct909, 08:04 PM

P: 107

can you tell me the answer and i will figure it out, because i don't know much about that equation yet...
ty ! 



#12
Oct909, 11:07 PM

Mentor
P: 39,589

Like, look at the 3rd figure down in this wiki article: http://en.wikipedia.org/wiki/Right_hand_rule It shows you how the magnetic B field circulates around a currentcarrying wire. Does that help? 



#13
Oct909, 11:38 PM

P: 113





#14
Oct1009, 10:18 PM

P: 107

thx for all 


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