The emf induced in the ring as the field changes is expressed as:

$\overline{){\mathbf{\epsilon}}{\mathbf{=}}\frac{\mathbf{-}\mathbf{N}{\mathbf{\pi r}}^{\mathbf{2}}\mathbf{\u2206}\mathbf{B}}{\mathbf{\u2206}\mathbf{t}}}$ where **ε **is the emf induced in the ring as the magnetic field changes, **N **is the number of turns, **ΔB** is the change in the magnetic field, **r** is the radius of the circular ring, and **Δt **is the time interval.

The resistance of the wedding band is given by:

$\overline{){\mathbf{R}}{\mathbf{=}}\frac{\mathbf{\rho}\mathbf{L}}{\mathbf{A}}}$, where **ρ** is the resistivity of the band, **L **is the length of the band, and **A **is the area of the band.

The length of the wedding band is:

$\overline{){\mathbf{L}}{\mathbf{=}}{\mathbf{2}}{\mathbf{\pi r}}}$, where **r **is the radius of the band.

A TMS (transcranial magnetic stimulation) device creates very rapidly changing magnetic fields. The field near a typical pulsed-field machine rises from 0 T to 2.5 T in 200 μs . 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.

Part A

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

Express your answer to two significant figures and include the appropriate units.

ε = ___________

Part B

If the band is gold with a cross-section area of 4.0 mm^{2}, what is the induced current? Assume the band is of jeweler's gold and its resistivity is 13.2 x 10^{10} Ω•m.

Express your answer to two significant figures and include the appropriate units.

I = ____________

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the !! Review: Faraday's + Lenz's Laws concept. If you need more !! Review: Faraday's + Lenz's Laws practice, you can also practice !! Review: Faraday's + Lenz's Laws practice problems.