 Another special case occurs when formula_10 is purely real (formula_48) and formula_49 is purely imaginary (formula_50), that is, it is a reactance.In this case,

Since

then

showing that all the incident wave is reflected, and none of it is absorbed in the termination, as is to be expected from a pure reactance.There is, however, a change of phase, formula_54, in the reflection given by

A discontinuity, or mismatch, somewhere along the length of the line results in part of the incident wave being reflected and part being transmitted onward in the second section of line as shown in figure 5.