A2L Item 246

Goal: reason and link electrical quantities

Source: 283-Del C, E, U, etc. – cstV

parallel conducting plates form a capacitor. With a metal cylinder of
length half the plate separation inserted between the plates, it is
connected to a battery with potential ΔV. The cylinder is now removed.
Which of the quantities C, ΔV, Q, E, and U change?

  1. C, E, and U only
  2. Q and U only
  3. C and U only
  4. E and U only
  5. Q, ΔV, and U only
  6. ΔV and E only
  7. C and Q only
  8. None of the above



(8) Since ΔV does not change, E must because the distance between
plates doubles. If E changes, so must Q. If Q changes, so must C.
Finally, that U chages can be seen in a variety of ways.

There are many good follow up questions, such as: How would the
quantities change if the cylinder was made of a dielectric material?