MIT 8.02 Electricity and Magnetism, Spring 2002 88 Online
OpenStudy (anonymous):

Consider a parallel plate capacitor created by sandwiching a 2 mm thick wire between two metal plates. The central metal core of the wire is 1 mm, covered by 0.5 mm of plastic (hence the total 2 mm distance between the plates). Now 'd' here will be 2mm, area=> 2 cm2. What is the type of plastic used often(P.V.C- dielec. const.=>3)? What is the capacitance: 1. When there is no potential in the wire( i.e. the wire is not connected). 2. When the wire is connected to 220 V supply only on the +ve side (i.e. -ve terminal is not connected).

OpenStudy (anonymous):

Continuation... 3. When the wire is connected to 220 V supply and carrying 5A current. The 1st question is easy; Please answer Question 2 and 3. Please explain whether the capacitance will change in questions 1 and 2 and 3.

OpenStudy (anonymous):

I was thinking that the capacitance will change in question 2 as the +ve potential in the wire would attract the electrons in the plastic (hence changing the capacitance). Is it so? +ve => Positive -ve => Negative