Question 7.8 :

Suppose the initial charge on the capacitor in Exercise 7.7 is 6 mC. What is the total energy stored in the circuit initially? What is the total energy at a later time?


 

Given Capacitance value of the capacitor, C = 30 μF = 30 × 10 – 6 F

Inductance of the inductor, L = 27 mH = 27 × 10 – 3 H

Charge on the capacitor, Q = 6 mC = 6 × 10 – 3 C

Total energy stored in the capacitor can be calculated as :

 à E=12×Q2C=12(6×103)230×106=610=0.6J

Total energy at a later time will remain the same because energy is shared between the capacitor and the inductor.