A TMS (transcranial magnetic stimulation) device creates very rapidly changing magnetic fields. The field near a typical pulsed-field machine rises from \(0 \mathrm{~T}\) to \(2.5 \mathrm{~T}\) in \(200 \mu\) s. Suppose a technician holds his hand near the device so that the axis of his 2.0-cm-diameter wedding band is parallel to the field.

a. What emf is induced in the ring as the field changes?

b. If the band is made of a gold alloy with resistivity \(6.2 \times 10^{-8} \Omega \cdot \mathrm{m}\) and has a cross-section area of \(4.0 \mathrm{~mm}^{2}\), what is the induced current?