Halliday, Resnick & Walker — Induction and Inductance: Problem 44

44 Figure 30-40a shows a wire that forms a rectangle ($W = 20\text{ cm}$, $H = 40\text{ cm}$) and has a resistance of $5.0\text{ m}\Omega$. Its interior is split into three equal areas, with magnetic fields $\vec{B}_1$, $\vec{B}_2$, and $\vec{B}_3$. The fields are uniform within each region and directly out of or into the page as indicated. Figure 30-40b gives the change in the $z$ components $B_z$ of the three fields with time $t$; the vertical axis scale is set by $B_s = 4.0\text{ }\mu\text{T}$ and $B_b = -2.5B_s$, and the horizontal axis scale is set by $t_s = 2.0\text{ s}$. What are the (a) magnitude and (b) direction of the current induced in the wire?