You are holding a compass 3.50 m from a long straight electrical supply wire that is carrying a direct current perpendicularly to the local direction of the Earth's magnetic field. Instead of orienting to any consistent "north" direction, the compass needle swings aimlessly no matter how you tilt or shake the instrument. The strength of the Earth's magnetic field at your location is 5.12×10?5 T. What is the magnitude of the current carried by the wire?