Answer to Question #92965 in Electricity and Magnetism for jane montgomery

Question

A permanent horseshoe magnet is mounted so that the magnetic field lines are vertical, as in the diagram below. If a student passes a straight wire between the poles in a horizontal plane and pulls it toward herself, (so in the diagram it would be coming out of the screen), the magnetic force is from right to left. Which is the north pole of the magnet?

Answer 1

Since there is no picture, draw the situation:

Remember the left-hand rule: if a field goes inside your opened left palm, four fingers are located in the direction of the current (or direction of motion of positive charges), your thumb positioned at 90 degrees relatively to other fingers will show the direction of the Lorentz force:

Hence, the north pole is at the bottom as shown in the first figure (because the field always comes from the North pole to the South pole).