Two positive point charges of $10 \ \mu C$ and $12 \ \mu C$ are placed $10 \ cm$ apart in air. The work done to bring them $6 \ cm$ closer is (in $J$)

$A$ molecule of a substance has a permanent electric dipole moment of magnitude $10^{-29} \; C \; m$. $A$ mole of this substance is polarized (at low temperature) by applying a strong electrostatic field of magnitude $10^{6} \; V \; m^{-1}$. The direction of the field is suddenly changed by an angle of $60^{\circ}$. Estimate the heat released (in $J$) by the substance in aligning its dipoles along the new direction of the field. For simplicity,assume $100 \%$ polarization of the sample.

Write an equation for the electric potential due to an electric dipole and state its important features. Discuss its special cases.

Consider the configuration of a system of four charges each of value $+q$. The work done by an external agent in changing the configuration of the system from Figure $(1)$ to Figure $(2)$ is:

An electric dipole of dipole moment $6 \times 10^{-6} \ Cm$ is placed in a uniform electric field of magnitude $10^6 \ V/m$. Initially,the dipole moment is parallel to the electric field. The work that needs to be done on the dipole to make its dipole moment opposite to the field will be . . . . . . $J$.

$A$ dipole having dipole moment $p$ is placed in front of a solid uncharged conducting sphere as shown in the diagram. The net potential at point $A$ lying on the surface of the sphere is :-