
#1
May609, 12:23 PM

P: 223

1. The problem statement, all variables and given/known data
The question actually asks for the equation for the magnetic field for the rotating disc; but all I'm after is the direction of the magnetic field. 2. Relevant equations None were given; but I've been using: [tex] \nabla \times \vec{E} = \frac{\partial \vec{B}}{\partial t}[/tex] 3. The attempt at a solution When I use the above equation I get two components to the magnetic field: [tex]\hat{r}[/tex] and [tex]\hat{\theta}[/tex]. That doesn't really make a lot of sense to me. What am I missing? 



#2
May609, 12:40 PM

P: 1,636

The cross product will give you the direction.




#3
May609, 12:44 PM

HW Helper
P: 5,004





#4
May609, 01:29 PM

P: 223

Direction of Magnetic Field for a Charged Rotating Disc
waht  Thanks. And that part I understand just fine. There is only a zcomponent of the electric field, so when I do a cross product, I get both an rcomponent and a thetacomponent.
gabbagabbahey  So the way you're describing it, the magnetic field seems to come up at the center of the disk, and then moves out and around to the bottom circling back up along the zaxis again? 


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