Originally posted by Scott35:

Quick answers:

If DC, the total resistance is 7 ohms.

If AC, and one element is in reality some type of Reactance, then total Impedance is 5 ohms.

If AC, and all elements are pure resistance [true power only - no Reactance, or very minimal Reactance], then 7 ohms is the total resistance.

Scott SET

I am assuming that they were talking DC, however if the reactance is unknown how do you come up with a 5 ohm impedance and if there is a reactance there should be a corresponding phase angle. ???Or the impedance of a two terminal device is defined as follows; Voltage across the element(v(t))/ current through the element i

(t), when v(t) and i(t)have the sink reference relation and when v(t) and I(t)each vary as eEXPst.