Answer: A toroid is a solenoid-like coil bent into a circle (Fig. 26.52a). Toroids are

Chapter 26, Problem 88

(choose chapter or problem)

A toroid is a solenoid-like coil bent into a circle (Fig. 26.52a). Toroids are the configuration of choice in magnetic-confinement nuclear fusion experiments, which, if successful, could provide us with an almost unlimited energy source using deuterium fuel extracted from seawater. The ITER consortium, an international collaboration, is building a large toroidal fusion experiment in France; its expected to be the first fusion device to produce energy on a large scale. Figure 26.52b shows a cross section of a toroid, with current emerging from the page at the inner edge and descending at the outer edge. The black circle is an Amprian loop The magnetic field associated with the toroid is nonzero a. only within the hole in the donut-shaped coil. b. only within the region bounded by the coils. c. only outside the coils. d. everywhere.