A capacitor with plates separated by distance d is charged to a potential difference V C .

Question:

A capacitor with plates separated by distance d is charged to a potential difference ΔV_C. All wires and batteries are disconnected, then the two plates are pulled apart (with insulated handles) to a new separation of distance 2d.
a. Does the capacitor charge Q change as the separation increases? If so, by what factor? If not, why not?
b. Does the electric field strength E change as the separation increases? If so, by what factor? If not, why not?