What is the impedance in a theoretical LC circuit?
What is the impedance in a theoretical LC circuit?


In series:

$$Z = j\omega L+\dfrac{1}{j\omega C}$$

$$\verb/ if /Z = 0 \verb/ then / \omega L= \dfrac{1}{\omega C}$$

$$\omega = \dfrac{1}{\sqrt{LC}}$$


  In theory (assuming superconductivity), since there is no resistance
  and thus purely imaginary impedance, would the signal oscillate
  forever between the inductor and capacitor in an LC circuit?


In theory, with zero losses, yes. However, infinite current will be taken from the source and infinite voltages will develop across L and C. It's a theoretical question so that isn't a problem!