Given that,
C1=5µF,C2=C3=10µF and
E=20V When the switch is connected to point
A.
Then, situation of the circuit is shown below.
Charge stored in
C1,
Q=C1V1=C1E=5×20µC=100µC When switch is connect to point
B, then situation circuit is shown below.
The charge
Q1 will start to distribute through,
C2 and
C3 to make the potential difference
V across all the three capacitors
C1,C2 and
C3.
Now, common potential difference,
V=‌| ‌ Total charge ‌ |
| ‌ Total capacity ‌ |
=‌ where,
V1=20V, but
V2=V3=0V ∴‌‌V=‌=‌=4V Now, charge on
C3,q3=C3V ‌‌=10×4µC ‌‌=40µC