7. A single loop circuit contains a mysterious box "W", with two wires sticking out of it: See figure below. 5.0 V + _ I 10mA + ' + ' | I 3 0 V 4.0 V A) At some instant, the current around the loop is 10mA, in the direction shown. Show a calculation of the voltage across the box W. Indicate which side is the higher potential. (Hint: This is just one big "loop\"; use the appropriate \"law\"!) B) You open the box to discover that "W" is just a ZDmF capacitor. Find the charge on each plate of the capacitor at this moment. (Hint: use your answer to part A.) C) You keep watching the capacitor. How do you expect your answer to part B to change over time? If it is changing, is it increasing or decreasing, and for roughly how long? (Hint: The current may not stay the same.)