Two capacitors $C_1$ and $C_2$ are charged to $120\ V$ and $200\ V$ respectively. It is found that connecting them together the potential on each one can be made zero. Then

A capacitor is made of two square plates each of side $a$ making a very small angle $\alpha$ between them, as shown in figure. The capacitance will be close to

A cylindrical capacitor has two co-axial cylinders of length $15\; cm$ and radii $1.5 \;cm$ and $1.4\; cm .$ The outer cylinder is earthed and the inner cylinder is given a charge of $3.5\; \mu \,C .$ Determine the capacitance of the system and the potential of the inner cylinder. Neglect end effects (i.e., bending of field lines at the ends).

Assertion : The total charge stored in a capacitor is zero.

Reason : The field just outside the capacitor is $\frac{\sigma }{{{\varepsilon _0}}}$. ( $\sigma $ is the charge density).

$1000$ small water drops each of capacitance $C$ join together to form one large spherical drop. The capacitance of bigger sphere is ......... $C$

What physical quantities may $X$ and $Y$ represent ? ($Y$ represents the first mentioned quantity)