(3%) Problem 30: A parallel-plate capacitor has a capacitance of c1 =9 muF when

Question

(3%) Problem 30: A parallel-plate capacitor has a capacitance of c1 =9 muF when full of air and c2 =35 muF when full of a dielectric oil at potential difference of 12 V. Consider the vacuum permittivity to be epsilon not = 8.85 x 10^-12 C^2/(N.m^2). 33% Part (a) Input an expression for the permittivity of the oil Epsilon. 33% Part (b) What js the permittivity of this oil in C^2/(N.m^2)? 33% Part (c) How much more charge delta q in C does the capacitor hold when filled with oil relative to when filled with air?

Explanation / Answer

a)capacitance of a parallel plate capacitor is given as

C=permitivity*area/distance between plates

so with the physical configuration remaining constant, capacitance is directly proportional to permitivity.

hence if permitivity of oil is epsilon,

then c1/c2=epsilon0/epsilon

==> epsilon=epsilon0*c2/c1

part b:

putting the values, we get permitivity=epsilon=34.41*10^(-12) C^2/(N.m^2)

part c: charge on a capacitor=capacitance*voltage

so difference in charge=difference in capacitance*voltage

=(35-9)*10^(-6)*12=312 uC

Related Questions

Navigate

• Browse (All)
• Browse #
• Subjects

---

---

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