Initially, the switch in the figure ( Figure 1 ) is in position A and capacitors
ID: 2139936 • Letter: I
Question
Initially, the switch in the figure (Figure 1) is in position A and capacitors C2 and C3 are uncharged. Then the switch is flipped to position B. Afterward, what are the charge on and the potential difference across each capacitor if V=80V?
Find Q1,Q2,Q3, and V1.V2.V3
Initially, the switch in the figure (Figure 1) is in position A and capacitors C2 and C3 are uncharged. Then the switch is flipped to position B. Afterward, what are the charge on and the potential difference across each capacitor if V=80V? Find Q1,Q2,Q3, and V1.V2.V3Explanation / Answer
C1 = 15 uF, C2 = 20 uF, C3 = 30 uF, V = 80V
later charges: q1, q2, q3
initial charge on C1 is Q = C1*V = 1200 uC
Q = q1 + q2 (1)
q2 = q3
q1/C1 = q2/C2 + q2/C3 (2)
from (2) we get
q2 = 16 q1/23
sub it into (1)
q1 = 23Q/39 = 707.6923076923077 uC
q2 = 492.3060869565217uC = q3
V1 = q1/C1 = 47.17933333333333V
V2 = q2/C2 =24.6153V
V3 = q2/C3 =16.4102V