Question

Two capacitors of capacitance 1.0 micro farad and 2.0 micro farads are each charged by being connected across a 5.0-volt battery. they are disconnected from the battery and then connected to each other with resistivity wires so that plates of opposite charges are connected together. What will be the magnitude of the final voltage across the 2.0-micro farad capacitor?

Answer 1

According to the question, resultant capacitance can be found by using the formula

$\frac{1}{C_s}=\frac{1}{C_1}+\frac{1}{C_2}$

or, $C_s=\frac{C_1{C}_2}{C_1+C_2}$

after putting all the values and calculating

we get,

$C_s=\frac{2}{3}\mu F$ comparing with the initial capacitance it is easy to see that the series capacitance on $2\mu F$ when in series with $1\mu F$

Now we can write,

$\frac{5V}{3}=1.6667V=1.7V$

Hence the magnitude of the final voltage is 1.7 V