Physics Electrostatics Level: High School

An air dielectric parallel-plate capacitor and the charging source is disconnected. A Mica dielectric is slipped between the plates. Which of the following happened?

1) The stored energy increases.

2) The stored energy decreases.

3) The capacitance is designed and the voltage across the plates is increased.

4) The capacitance is increased and the voltage across the plates is increased.