Two capacitors with C_1 = 3 muF and C_2 = 6 muF are individually connected to 9

Question

Two capacitors with C_1 = 3 muF and C_2 = 6 muF are individually connected to 9 Volt and 12 Volt batteries, respectively. After being charged, they are placed in a circuit with each other in such a way that the positive plate of one is connected to the negative plate of the other. Determine the final charge on each capacitor. Consider the arrangement of capacitors in the circuit of the figure. (a) Find the effective capacitance between points a and b. (b) Find the charge associated with the 3 muF capacitor.

Explanation / Answer

5(b) C1 = 18 uF, C2 = 3 uF, C3 = 6 uF, C4 = 4 uF

in series combination C23 = C2+C3 = 3+6

C23 = 9 uF

C123 =C1*C23/(C1+C23) = (18*9)/(18+9)

C123 = 6 uF

Cab = C1234 = C123 +C4 = 6 +4

Cab = 10 uF

(b) V = 10 V

in parallel combination potential is constant

V4 = 10 V

V123 = 110 V

Q123 = 110*6 = 660 uC

in series combination charge is constant

Q1 = 660 uC

Q23 = 660 uC

V23 = 660/9 = 73.33 V

in parallel combination potential is constant

V2 = 73.33 V

Q2 = 73.33*3 = 220 uC

charge across 3 uF capacitor is 200 uC

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

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