The charge on capacitor of capacitance $15\mu \mathrm{F}$ in the figure given below is

A parallel plate capacitor with plate area $A$ and plate separation $d=2 \mathrm{m}$ has a capacitance of $4 \mathrm{\mu F}$. The new capacitance of the system if half of the space between them is filled with a dielectric material of dielectric constant $K=3$ (as shown in figure) will be

Two capacitors having capacitance $C_1$ and $C_2$ respectively are connected as shown in figure. Initially, capacitor $C_1$ is charged to a potential difference $V$ volt by a battery. The battery is then removed and the charged capacitor $C_1$ is now connected to uncharged capacitor $C_2$ by closing the switch $S$. The amount of charge on the capacitor $C_2$, after equilibrium, is

Given below are two statements : One is labelled as Assertion (A) and other is labelled as Reason (R).

Assertion (A): Non-polar materials do not have any permanent dipole moment.

Reason (R): When a non-polar material is placed in an electric field, the centre of the positive charge distribution of its individual atom or molecule coincides with the centre of the negative charge distribution.

In the light of above statements, choose the most appropriate answer from the options given below.

If a charge $q$ is placed at the centre of a closed hemispherical non-conducting surface, the total flux passing through the flat surface would be

Three identical charged balls each of charge $2C$ are suspended from a common point $P$ by silk threads of $2 \mathrm{m}$ each (as shown in figure). They form an equilateral triangle of side $1 \mathrm{m}$. The ratio of net force on a charged ball to the force between any two charged balls will be