Halliday, Resnick & Walker — Induction and Inductance: Problem 74

74 A wire is bent into three circular segments, each of radius \( r = 10 \text{ cm} \), as shown in Fig. 30-55. Each segment is a quadrant of a circle, \( ab \) lying in the \( xy \) plane, \( bc \) lying in the \( yz \) plane, and \( ca \) lying in the \( zx \) plane. (a) If a uniform magnetic field \(\vec{B}\) points in the positive \( x \) direction, what is the magnitude of the emf developed in the wire when \( B \) increases at the rate of \( 9.0 \text{ mT/s} \)? (b) What is the direction of the current in segment \( bc \)?