Capacitor Diagram/ charge difference/ potential difference

xzibition8612

1. The problem statement, all variables and given/known data
See attachment "problem 1" and "problem 2"


2. Relevant equations

E=(Q/A)/e0

3. The attempt at a solution
See attachment "work 1"

For "problem 2", (c) I wrote this:

Qf is greather than Qi because E is bigger.

For (d), I don't know how to do this part. Something to do with the electric field of a capacitor?

Thanks a lot!

Attached Thumbnails