Question

this is part c of my last question...

c) Determine the time constants for charging the capacitor through the resistance R in the RC circuit and for establishing the current in the inductor through the same resistance in the LC circuit.

Answer 1

In an RC circuit
\[\tau = RC\]

In an LC circuit you wouldn't have a true charging time constant, you could have a peak frequency or an oscillating frequency for the energy going from the inductor to the condenser back and forth... Do you mean an RL circuit?
In an RL circuit
\[\tau =\frac{L}{R}\]