1) A parallel-plate capacitor has a capacitance of c1 = 3.5 uF when filled with air and c2 = 23 uF when filled with a dielectric oil at potential difference of 12 V. Take the vacuum permittivity to be Eo = 8.85 * 10-12 C2/(N*m2).
a) Input an expression for the permittivity of the oil ?.
b) What is the permittivity of this oil in C2/(N?m2)?
c) How much more charge (delta q) in C does the capacitor hold when filled with oil relative to when its filled with air?
2)A nervous physicist worries that the two metal shelves of his wood frame bookcase might obtain a high voltage difference if charged by static electricity, perhaps produced by friction.
a) What is the capacitance of the empty shelves if they have area 1*103 cm2 and are 0.19 m apart in F?
b) What is the potential difference between them if opposite charges of magnitude 2.00 nC are placed on them in V?
c) To show that this voltage poses a small hazard, calculate the energy stored in J.