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 10-5 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 45-m 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 high-voltage 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 ...
- physics - A uniform horizontal wire with a linear mass density of 0.48 g/m ...
- physics - A straight horizontal wire carries a current of 3.55 μA. A proton...
- Physics - Help please A wire carries a current of 5.2 A from east to west ...

More Related Questions