Question

Two capacitors of 2uf and 3uf are charge 150 volt and 120 volt respectively. The plates of capacitor are connected as shown in the figure. A discharged capacitor of capacity 1.5uF falls to the free ends of the wire

Answer 1

@radar @IrishBoy123 @

Answer 2

Well, when you complete the circuit, the current will flow until the voltages have balanced out. I'm assuming you want the steady state voltages?

Essentially, if the voltages weren't equal in the steady state, there would be a potential difference. If there was a potential difference (especially in this resistance free circuit), current would flow and the voltage would balance back out..

So in this closed circuit there is no energy dissipation, and charge cannot be created or destroyed. So you know the total charge based on the given initial values, and you know that the final voltages are all equal. That should be enough to get you going :)

Answer 3

when we connect the two capacitors C_1 and C_2, a charge motion will occur between them, in order to establish a equilibrium potential V_e across each of them. So we can write:
before connecting C_1 and C_2 , we have:
\[\begin{gathered}
{Q_1} = {C_1}{V_1} \hfill \\
{Q_2} = {C_2}{V_2} \hfill \\
\end{gathered} \]
after connecting C_1 and C_2 together, we have:
\[\begin{gathered}
Q{'_1} = {C_1}{V_e} \hfill \\
Q{'_2} = {C_2}{V_e} \hfill \\
\end{gathered} \]
now, since electric charge is conserved, we can write:
\[{Q_1} + {Q_2} = Q{'_1} + Q{'_2}\]
from which we get:
\[{V_e} = \frac{{{C_1}{V_1} + {C_2}{V_2}}}{{{C_1} + {C_2}}}\]

Answer 4

Need more info...... Is the problem what will be the voltage or charge on each capacitor when the uncharged 1.5 uF capacitor is connected to A and B ??

Answer 5

Note that the voltage between A & B is 270 volts before any connection is made.

Answer 6

Is the problem determine the voltages across each capacitor after the switches are closed connecting the 1.5uF capacitor in series with the other two series connected capacitors?