Halliday, Resnick & Walker — Induction and Inductance: Problem 26

26 In Fig. 30-31, two straight conducting rails form a right angle. A conducting bar in contact with the rails starts at the vertex at time \( t = 0 \) and moves with a constant velocity of \( 8.90 \text{ m/s} \) along them. A magnetic field with \( B = 0.350 \text{ T} \) is directed out of the page. Calculate (a) the flux through the triangle formed by the rails and bar at \( t = 3.00 \text{ s} \) and (b) the emf around the triangle at that time. (c) If the emf is \( \mathcal{E} = at^n \), where \( a \) and \( n \) are constants, what is the value of \( n \)?