# Homework Help: Magnetic forces in a wire

1. Feb 21, 2008

### arod2812

1. The problem statement, all variables and given/known data
A long, straight, vertical segment of wire traverses a magnetic field of magnitude 2.0 T in the direction shown in the diagram. The length of the wire that lies in the magnetic field is 0.060 m. When the switch is closed, a current of 4.0 A flows through the wire from point P to point Q.
Which one of the following statements concerning the effect of the magnetic force on the wire is true?

The wire will have no net force acting on it.
The wire will be pushed to the right.
The wire will be pushed downward, into the plane of the paper.
The wire will be pushed upward, out of the plane of the paper.
The wire will be pushed to the left.

2. Relevant equations
How is the wire being pushed?? Should I use the Right Hand Rule? If so, what does it tell me about how the wire is being pushed?

3. The attempt at a solution
I used the equation F=ILBsin(theta) but it don't understand how these values tell me about the direction.

2. Feb 21, 2008

### blochwave

Well the equation you're using is for the magnitude of the force vector, which is found with a cross product, so yes you use the right hand rule but also the proper equation

You would also have to post the diagram for us to be more helpful