Phase Behavior of RL Circuits: Explained

[driedupfish]

Homework Statement

http://img14.imageshack.us/img14/7694/picture1yao.png [Broken]

second part: the voltages across the resistor and the inductor are...




The answer given is always out of phase. Can someone explain why?
If the it is in resonance, wouldn't the impedance be equal to the resistance? Therefore, voltage across the generator and the resistor would be in phase?
The answer given for the second part is also always out of phase. Can someone explain that as well?
Thanks

 

[Feldoh]

Perhaps if you solved the differential equation obtained using Kirchoff's laws for voltage it might give you some insight.