If you have an air dielectric capacitor and then completely fill the gap between the plates with teflon(PTFE), making it a teflon dielectric cap, approximately what will the new capacitance be?

0.5 times the air value

1.4 times the air value

2 times the air value

4 times the air value

Answer: Capacitance is proportional to the dielectric constant...air is Er=1, and teflon is Er~2.1, so capacitance is twice the air value.