Inductance is usually denoted by L and ismeasured in SI units of henries (also written henrys, andabbreviated H), named after Joseph Henry, a contemporary ofMichael Faraday. The EMF E produced in a coil withinductance L is, according to Faraday's law,given by

E=?L?I?t.

Here ?I/?t characterizes the rate atwhich the current I through the inductor ischanging with time t.

Based on the equation given in the introduction, what are theunits of inductance L in terms of the unitsof E, t, and I (respectivelyvolts V, seconds s, and amperes A)?

What EMF is produced if a waffle iron that draws 2.5 amperes andhas an inductance of 560 millihenries is suddenly unplugged, so thecurrent drops to essentially zero in 0.015 seconds?