The body contains many small currents caused by the motion of
ions in the organs and cells. Measurements of the magnetic field
around the chest due to currents in the heart give values of
about 1.1 μG. Although the actual currents are
rather complicated, we can gain a rough understanding of their
magnitude if we model them as a long, straight wire.
a. If the surface of the chest is 4.20 cm from
this current, how large is the current in the heart?