Question

3. You are given three capacitors C1 10.0 uF, C2 = 20.0 uF and C3 = 40.0 uF. The capacitors are connected as shown. The capacitors start out discharged, and then a battery (not shown) is connected between points A and B and all three capacitors become fully charged. C1 C2 A) [3 pts] Using and “=”, rank from greatest to least the charges on the A capacitors, Q1, Q2, Q3. Using physical principles (not just rules), explain. HA C3 B H B) [3 pts] Now, assume the maximum voltage rating of each of these capacitors is 100 V. If this voltage rating is exceeded across any of these capacitors, that capacitor will be destroyed. What is the maximum battery voltage you can apply (between points A and B) that will not blow up any of the capacitors?

Answer 1

Capacitors in Series have the same current flowing through them as iT = i1 = i2 = i3 etc. Therefore each capacitor will store the same amount of electrical charge, Q on its plates regardless of its capacitance.

Q1=Q2=Q3

( = 10 MF ₂ = = 20 MF ₂ = 40 MF Ci ₂ (3 AHIMI Applying KVL, th Q + + V Z V C (2 C3 Now given (a) max z 100 V Qmax Cmin z 100V > Amax = 100% (min 100 X 10 MF 1000 uc L', Vmax = 1000 10 + 1000 20 + - 1000 40 175 v