Answer:
3.98V
Explanation:
Given
Pontential difference V as 3v
Energy delivered is 30%,
Recall that Enery E=1/2cv^2 from this E=V^2(since Current C is not provided we can assume a value 2)
So E=V^2
E=3^2=9
At full charge E=9,30%of 9,0.3*9=2.7 energy in capacitor is 9-2.7=6.3
But E=V^2
✓E=V
✓6.3=3.98V