Find Vemf (between points 1 and 2) and it's polarity at t = 0. This is a worked out example in my textbook. I have omitted details because my question is specifically on the polarity.
Lenz's law says that an induced electromotive force (emf) always gives rise to a current whose magnetic field opposes the original change in magnetic flux.
Vemf = -dΦ/dt
We first find the flux Φ and Vemf which are function of time. We compute dΦ/dt at t = 0. Then Vemf = -dΦ/dt.
We find that dΦ/dt > 0, so the magnetic field B is increasing. To counter-act this change, I must be in the direction given in the picture. Everything is ok at this point.
Now here is where I get lost. My textbook says:
I thought I always is from the higher potential to the lower potential. Which should make terminal 1 at a higher potential than terminal 2 considering the direction of I. It seems like the textbook have it backwards.At t=0, dΦ/dt > 0 and Vemf = -188.5 V. Since the flux is increasing, the current I must be in the direction shown in the figure in order to satisfy Lenz's law. Consequently, terminal 2 is at a higher potential than terminal 1 and Vemf = V1 - V2
What am I missing?