Chapter 21, Problem 28P

(a)

To determine

The sign of $\Delta i/\Delta t$.

(b)

To determine

The direction of induced emf.

(c)

To determine

Show that the correct sign for $v_L=L\frac{\Delta i}{\Delta t}$.

(d)

To determine

Find the sign of $\Delta i/\Delta t$, the direction of induced emf and show that the sign for $v_L=L\frac{\Delta i}{\Delta t}$, if the current flows to left through the inductor and is decreasing in magnitude.