Question

A 10 microF capacitor with an initial charge Q₀ is connected across an 8 milliH inductor. If the circuit is completed at time t = 0, how soon (in millisec) afterward will the charge on the capacitor reverse sign and become equal to -Q₀? 

Answer 1

For this LC circuit Q = Q0cos(ωt) which is equal to –Q₀ when ωt = π so that