confused on Magnetic fields!! Hello everyone, we just started a chapter on magentic fields due to currents and i'm pretty lost. I'm looking at the homework and its making no sense to me.. I read the section and yet its not helping either. It gives lots of formulas but doesn't really explain how to interpret them. For instance: Figure 29-25 shows four arrangements in which long parallel wires carry equal currents directly into or out of the page at the corners of identical squares. Rank the arrangements according to the magnitude of the net magnetic field at the center of the square, greatest first. (Use only the symbols > or =, for example a=b>c>d.) http://www.webassign.net/hrw/hrw7_29-25.gif I said: a>d>b=c which was wrong How could u apparoach this? I understand if a current is going into the page and another current is going out of the page, u get a repulisve force, and if they are both going in the same direction, in or out of the page, u get an attractive force, but whats that mean about magntiude? also: http://www.webassign.net/hrw/hrw7_29-24.gif i'm suppose to figure out: f the net magnetic field due to the two currents is to be zero at point P, describe the current i2 in the right hand wire. (Select all that apply.) into the page out of the page i2 > i1 i2 < i1 i2 = i1 I don't want the answers, I would like someoen to epxlain to me how to intrepert this, or can any of you direct me to a webpage that explains the rules? Thanks!