Neurons in our bodies carry weak currents that produce detectable magnetic fields. A technique called magneto encephalography, or MEG, is used to study electrical activity in the brain using this concept. This technique is capable of detecting magnetic fields as weak as 1.0 10-15 T. Model the neuron as a long wire carrying a current and find the current it must carry to produce a field of this magnitude at a distance of 4.7 cm from the neuron.