Please wait for the animation to completely load.

Find the current in the red wire. You can drag the red wire around and read the force/length on it. You can also read the value of the magnetic field at given points in the animation when your mouse is not on a wire (position is given in centimeters, magnetic field strength is given in 10^-5 tesla, and force/length is given in newtons/meter). You can also turn the current in the red wire on and off by pushing the buttons. Restart.

Problem authored by Anne J. Cox.
Script authored by Wolfgang Christian and Mario Belloni and modified by Anne J. Cox.