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In the figure shown below, all elements used are ideal. For time t < 0,S1 remained closed and S2 open. At t = 0, S1 is opened and S2 is closed. If the voltage Vc2 across the capacitor Cc at t = 0 is zero, the voltage across the capacitor combination at t = 0+ will be
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- 1 V
- 2 V
- 1.5 V
- 3 V
Correct Option: D
For t < 0, s1 in closed and s2 open
Qc1 = C1 V = 3 C
Qc2 = 0
At t = 0, S1 is opened and S2 is closed.
Now, let Q ' c1 and Q ' c2 is the change stored after redistribution
then, Q ' c1 + Q ' c2 = Q c1 + Q c2 = 3C ...(A)
| = | ||||
| c1 | c2 |
[Equal potential across C1 and C2].
| ⇒ | = | .......(B) | ||
| 1 | 2 |
By equation (A) and equation (B),
Q 'c1 = 1C as Q' c2 = 2C
and voltage across capacitor combination is,
| = | = 1 volt | |
| C1 |
