Chapter 23, Problem 86GP

BIO Transcranial Magnetic Stimulation Transcranial magnetic stimulation (TMS) is a noninvasive method for studying brain function, and possibly for treatment as well. In this technique, a conducting loop is held near a person’s head, as shown in Figure 23-50. When the current in the loop is changed rapidly, the magnetic field it creates can change at the rate of 3.00 × 10⁴ T/s. This rapidly changing magnetic field induces an electric current in a restricted region of the brain that can cause a finger to twitch, bright spots to appear in the visual field (magnetophosphenes), or a feeling of complete happiness to overwhelm a person. If the magnetic field changes at the previously mentioned rate over an area of 1.13 × 10⁻² m², what is the induced emf?