Problem 22.47 MC ) 10 of 12 Constants Part A Air isn\'t a perfect electric insul

Question

Problem 22.47 MC ) 10 of 12 Constants Part A Air isn't a perfect electric insulator, but it does have a very high resistivity. Dry air has a resistivity of approximately 3 × 1013 ·m. Assume we have a capacitor with square plates 12 cm on a side separated by 2.0 mm of dry air Assuming that the air between the capacitor's plates can be treated like any other resistor, find its resistance value. Express your answer using three significant figures. View Available Hint(s) Submit Part B If the capacitor is charged to 210 V,what current will flow between the plates of the capacitor? Make two approximations: That the potential difference doesnt change as the charge fows and that the air obeys Ohm's law. Express your answer using three significant figures. View Available Hint(s) Submit

Explanation / Answer

given resistivity of air rhoa = 3*10^13 ohm m

side of capacitor plate, a = 12 cm = 0.12 m

plate seperation, d = 2 mm = 2*10^-3 m

A. resistance of the air inside the capacitor plates = R

R = rhoa*d/a^2 = 4166666666666.666 ohm = 4.1666*10^12 ohm

B. voltage, V = 120 V

for the air following ohms law and tghe charg eon the capacitor plates remaining fairly constant

the current flow is

i = V/R = 0.288*10^-10 A

C. after one minute

charge lost = i*60 = 17.28*10^-10 C

initial Charge = Q = CV = V*a^2*epsilon/d

epsilon = 8.861*10^-12

hence

Q = 7.65*10^-9 C

so fraction of charge lost = 0.225692

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.