Two parallel plate capacitors X and Y, have the same area of plates and same separation between plates. X has air and Y with dielectric of constant 2 between its plates. They are connected in series to a battery of 12 V. The ratio of electrostatic energy stored in X and Y is
1
4 ∶ 1
2
1 ∶ 4
3
2 ∶ 1
4
1 ∶ 2