PHYSICS · Subjective · AP · Physics 2: Algebra-based · Electric Force Field and Potential · Electric Force Field and Potential
Problem
Four parallel-plate capacitors, each having the same plate separation d, are listed below. In every case the space between the plates is completely filled by the stated medium.
C1: air, plate area A
C2: air, plate area 2A
C3: glass (κ=4), plate area A
C4: mica (κ=6), plate area 2A
(a) Rank the four capacitors in descending order of capacitance. Justify each step of your ranking without performing any numerical calculation.
(b) If each capacitor is separately charged to the same potential difference V and then disconnected from the battery, rank them in descending order of the electrostatic energy stored. Give reasons for your answer.
(c) If instead each capacitor is connected across separate identical batteries that maintain the potential difference V while charging and afterwards, comment on whether your ranking in part (b) will change. Support your answer with qualitative reasoning.