Passage VI
A parallel-plale capacitor (PPC) stores electric charge on 2 separated plates when a voltage is applied across the plates. Figure 1 shows a PPC before (left) and after (right) it was filled with a dielectric (insulating material). The capacitance of an empty PPC, C0, is the amount of charge stored per unit of applied voltage. The capacitance of a filled PPC, Cκ, equals C0 multiplied by the dielectric constant, κ, of the filling material. Table 1 gives κ for 12 materials. Table 2 gives the dielectric strength, S (the maximum electric field strength at which a dielectric remains an insulator), for 7 of the materials.
32. Based on Table 1, the dielectric that fills the PPC shown in Figure 1 is most likely which material?
Your Answer is
Correct Answer is H
Explanation
Look at the seventh line of the text, Ck equals C0 multiplied by the dielectric constant, k. That is k=Ck /C0.
Look at the values on the two capacitance meters in figure 1, you can calculate k=10.4/2=5.2, go back to table 1, and find that only Pyrex glass satisfies