An inductor causes a 90 degrees phase shift. After reading the previous section, it's clear that the complex impedance can be written as:

So: |Z_R+L| = √(R²+X_L²) and arg(Z_R+L) = arctan(X_L/R).

As an example, we'll take a 10k resistor in series with a 15.9k inductor. The total (complex) impedance is 10k + 15.9kj. The absolute value is √(10k² + 15.9k²) = 18.78k. The phase shift in the current flow will be arctan(15.9k/10k) = 57.8 degrees.