# Physics

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Transcranial magnetic stimulation (TMS) is a noninvasive technique used to stimulate regions of the human brain. A small coil is placed on the scalp, and a brief burst of current in the coil produces a rapidly changing magnetic field within the brain. The induced emf can be sufficient to stimulate neuronal activity. One such device generates a magnetic field within the brain that rises from zero to 1.8 T in 100 ms. Determine the induced emf within a circle of tissue of radius 1.5 mm and that is perpendicular to the direction of the field.

• Physics -

dB/dt is 1.8/100E-6

Use Lenz's law:

V=d/dt (B*area)

• Physics -

1.27 E-4

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