Data recorded with the magnetometer is show below. During most of the recording the data is due to just the magnetic field of the Earth, but at about 3.3 s on the time axis the two ends of the wire are hooked up to a battery that causes a current to flow from right to left through the wire for about a second. While it flows, this current results in a big change on the z component of the magnetic field measured by the magnetometer, but no changes in the x and y components.

Magneiometer-suwz. v Bx .4 By .32 50 40 30 20 10 D E 10 cu . .20 all] .40 -50 760 00 05 ID IS 20 25 '30 35 4D 45 50 55 50 55 1:!- G imam In the box below, try to explain how the change in 32 (Le. upward) is consistent with the current flowing from right to Left through the wire, and also why the current causes no change in Bx and By. It may help you to know that the magnetic eld from a long straight wire forms circles around the wire, with the direction of the eld being related to the direction of the current by the right hand rule as shown in the image below. Electric current Magnetic eld