In a parallel plate capacitor with air between the plates, each plate has an area of $6\times10^{-3}~\text{m}^2,$ and the distance between the plates is $3~\text{mm}.$ The capacitance of the capacitor is:
1. $16.12~\text{pF}$
2. $17.71~\text{pF}$
3. $15.01~\text{pF}$
4. $11.32~\text{pF}$

The $6$ $\mu$F capacitor is initially charged to $2$ V (i.e. $V_B-V_A=2$ V) while the $3$ $\mu$F capacitor is uncharged. The switch is now closed. The final potential difference across the $3$ $\mu$F capacitor will be:
    

1. $4$ V

2. $\frac{4}{3}$ V

3. $2$ V

4. $\frac{8}{3}$ V

Three capacitors connected in series have a capacitance of $9~\text{pF}$ each. The potential difference across each capacitor if the combination is connected to a $120~\text V$ supply is:
1. $10~\text V$ 
2. $20~\text V$ 
3. $30~\text V$ 
4. $40~\text V$