Question

Which statements are true for two oppositely charged, isolated parallel plates: C = capacitance, U = stored energy (Q and -Q = charge on the plates)?

Note: Isolated plates can not lose their charge.

1) Inserting a dielectric decreases U.
2) When the distance is halved, Q stays the same.
3) When the distance is doubled, U increases.
4) Inserting a dielectric increases C.
5) Increasing the distance increases the Electric field.
6) Inserting a dielectric increases Q.
7) When the distance is doubled, C increases.