The work required to be done to assemble four particles,each having a charge $+q$,at the four corners of a square of side $a$ is .......

Three point charges $q, q$ and $-2q$ are placed at the corners of an equilateral triangle of side $L$. Calculate the work done by an external force in moving all the charges far apart without acceleration.

An electric dipole with dipole moment $p$ is placed in an electric field of intensity $E$. Initially,the dipole is parallel to the field. What is the work done by an external agent to rotate the dipole by $180^{\circ}$ in the electric field?

An electric dipole of moment $\overrightarrow{p}$ is lying along a uniform electric field $\overrightarrow{E}$. The work done in rotating the dipole through $90^{\circ}$ is $\left[\sin 0^{\circ}=\cos 90^{\circ}=0, \cos 0^{\circ}=\sin 90^{\circ}=1\right]$

Three point charges of $3 \mu C, 4 \mu C$,and $5 \mu C$ are arranged at the three corners of a right-angled triangle $ABC$ as shown in the figure. The work done in moving the charges at $A$ and $C$,so that the three charges are located at the three corners of an equilateral triangle of side $3 \text{ cm}$ is (in $J$)

$A$ system of two charges separated by a certain distance apart stores electrical potential energy. If the distance between them is increased,the potential energy of the system,