1. The problem statement, all variables and given/known data I'm confused about [question 16](http://image.prntscr.com/image/41a5c611927c44a7ac30104be3dd10ee.png) and [question 30](http://image.prntscr.com/image/a6aea3b9a8f04df9aca0dfe14054d4ce.png). The correct answers are e and a respectively. 2. Relevant equations 3. The attempt at a solution For 16, why did D not work? Intuitively, I chose E because of parallel plates that have equal electric fields, but what is the integral for choice D and E and why are they different? For 30, I thought higher voltage meant higher potential so I thought the answer should be C and D. Why is it A?