申論題

13.Figure (7) shows a rectangular loop of wire immersed in a nonuniform and varying magnetic field that is perpendicular to and directed into the page. The field's magnitude is given by B = 6t² x, with B in teslas, t in seconds, and x in meters. (Note that the function depends on both time and position.) The loop has width W = 3.0 m and height H = 2.0 m. What are the magnitude and direction of the induced emf around the loop at t = 0.20 s?