Posted by Justin on Thursday, February 10, 2011 at 6:42pm.
Suppose a straight 1.25 mm diameter copper wire could just "float" horizontally in air because of the force of the Earth's magnetic field B, which is horizontal, perpendicular to the wire, and of magnitude 5.00 multiplied by 105 T. What current would the wire carry?
I want to use the formula F=IlBsin(theta); but am confused as to what F would be, what does just "float" horizontally imply?

Physics  Christine, Tuesday, April 12, 2011 at 7:48pm
I won't be able to answer exactly, but we know that the net force on the wire would be zero. So it means that Force(gravity) = Force(magnetic)

Physics  Christine, Tuesday, April 12, 2011 at 9:37pm
Hey, I thought about it a little more and I have your answer here.
B = mu(naught) * I / (2pi * r)
You can solve for I in that equation. I hope it looks familiar.
mu(naught) = vacuum permeability
I = current
r = radius of wire
Answer This Question
Related Questions
 Physics  Suppose a straight 1.60mm diameter copper wire could just "float" ...
 physics  A horizontal, straight wire carrying 12 A current from east to west is...
 physics help  A straight horizontal sretch of copper wire carries a current of ...
 physics  A horizontal ,straight wire carying 12.0A current from west to east is...
 Physics  A 45m length of wire is stretched horizontally between two vertical ...
 Physics  The magnetic force on a straight wire .69 m long is 1.5 x 10^3 N. The...
 physics  A highvoltage power line carries a current of 120 A at a location ...
 Physics  A long, straight wire carrying a current of 317 A is placed in a ...
 magnetic field  A straight copper wire that is 1 milimeter in diameter carries ...
 physics  the magnetic force on a straight 0.15m segment of wire carrying a ...
More Related Questions