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Hey,

I've just been studying for my physics exam in a few days time and I'm trying to work out this problem,

a)the proof was straight forward and I wrote that the field is uniform over the cylinder because of cylindrical symmetry and c) I think was ok F = q(vxB) so q|v||B| going up the page so say z direction.

I'm just a bit stuck on the rest,

for b) I can't really picture how this think is set up, the field is into the page so by right hand rule the current flows to the right. But I'm not sure what its supposed to look like, would that mean the current is flowing anti-clockwise when you look at the cylinder from above? and I would just be found using the equation given, J = I/A = Eσ, we would probably need to find E, so using gausses law which a guassian cylinder inside the conductor, but then you would get the field at some radius within the cylinder involving a q which hasnt been provided in the question, like they didnt give a volume charge density. So I'm a little confused there.

For d) I am really not sure where to start with it, could anyone point me in the right direction?

and for e) I would of said that the kinetic energy went to electric potential energy cause the system is changing so the currents would form to counteract the change and eventually want to pull the cylinder in the opposite direction

Thanks a lot in advance

Heres the question 20/100 marks

http://img265.imageshack.us/img265/5363/32063619.jpg [Broken]

I've just been studying for my physics exam in a few days time and I'm trying to work out this problem,

a)the proof was straight forward and I wrote that the field is uniform over the cylinder because of cylindrical symmetry and c) I think was ok F = q(vxB) so q|v||B| going up the page so say z direction.

I'm just a bit stuck on the rest,

for b) I can't really picture how this think is set up, the field is into the page so by right hand rule the current flows to the right. But I'm not sure what its supposed to look like, would that mean the current is flowing anti-clockwise when you look at the cylinder from above? and I would just be found using the equation given, J = I/A = Eσ, we would probably need to find E, so using gausses law which a guassian cylinder inside the conductor, but then you would get the field at some radius within the cylinder involving a q which hasnt been provided in the question, like they didnt give a volume charge density. So I'm a little confused there.

For d) I am really not sure where to start with it, could anyone point me in the right direction?

and for e) I would of said that the kinetic energy went to electric potential energy cause the system is changing so the currents would form to counteract the change and eventually want to pull the cylinder in the opposite direction

Thanks a lot in advance

Heres the question 20/100 marks

http://img265.imageshack.us/img265/5363/32063619.jpg [Broken]

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