Suppose the initial charge on the capactor in the above question is 6 mC. What is the total energy stored in the capactor intially ? What is the total energy at later time ?

Explanation

Capacitance of the capacitor, C=`30muF=30xx10^(-6)F`
Inductance of the inductor, L`=27mH=27xx10^(-3)H`
Charge on the capacitor, Q=6mC=6`xx10^(-3)C`
Total energy stored in the capacitor can be calculated by the relation
`E=(1)/(2)(Q ^(2))/(C)`
`=(1)/(2) xx ((6xx10^(-3))^(2))/(30xx10^(-6)) `
`=(6)/(10)=0.6J`
Total energy at a later time will remain the same because energy is shared between the capacitor and the inductor.