Q.

A parallel plate capacitor of capacitance 2F is charged to a potential V. The energy stored in the capacitor is E1. The capacitor is now connected to another uncharged identical capacitor in parallel combination. The energy stored in the combination is E2. The ratio E2/E1 is            [2023]

1 2 : 1  
2 1 : 2  
3 1 : 4  
4 2 : 3  

Ans.

(2)

Initially,

Q1=CV=(2)V

E1=12CV2=12(2)V2=V2

Finally,

Charge on each capacitor,

       Q2=Q12=2V2=V

        E2=2(12Q22C)=V22

    E2E1=12