19.5 Capacitors and Dielectrics

Two parallel plate capacitors are otherwise identical, except the second one has twice the distance between the plates of the first. If placed in otherwise identical circuits, how much charge will the second plate have on it compared to the first?

1. four times as much
2. twice as much
3. the same
4. half as much

A parallel plate capacitor with adjustable-size square plates is placed in a circuit. How does the charge on the capacitor change as the length of the sides of the plates is increased?

1. it grows proportional to length²
2. it grows proportional to length
3. it shrinks proportional to length
4. it shrinks proportional to length²

A student was changing one of the dimensions of a square parallel plate capacitor and measuring the resultant charge in a circuit with a battery. However, the student forgot which dimension was being varied, and didn’t write it or any units down. Given the table, which dimension was it?

1. The distance between the plates
2. The area
3. The length of a side
4. Both the area and the length of a side

What charge is stored in a $\text{180 }\mu\text{F}$ capacitor when 120 V is applied to it?

What charge is stored in the capacitor in the example?

What voltage must be applied to an 8.00 nF capacitor to store 0.160 mC of charge?

What is the capacitance of a large Van de Graaff generator’s terminal, given that it stores 8.00 mC of charge at a voltage of 12.0 MV?

(a)What is the capacitance of a parallel plate capacitor having plates of area $\text{1}.\text{50 m}^{2}$ that are separated by 0.0200 mm of neoprene rubber? (b) What charge does it hold when 9.00 V is applied to it?

(a) A certain parallel plate capacitor has plates of area $\text{4}.\text{00 m}^{2}$, separated by 0.0100 mm of nylon, and stores 0.170 C of charge. What is the applied voltage? (b) What is unreasonable about this result? (c) Which assumptions are responsible or inconsistent?