For a short dipole placed at origin $O$,the dipole moment $P$ is along the $x$-axis,as shown in the figure. If the electric potential and electric field at point $A$ (at distance $r$ on the $x$-axis) are $V_0$ and $E_0$,respectively,then the correct combination of the electric potential and electric field,respectively,at point $B$ (at distance $2r$ on the $y$-axis) is given by

An electric dipole of length $0.5 \text{ }\mu\text{m}$ is placed with its axis making an angle of $30^{\circ}$ with a uniform electric field of $10^4 \text{ V/m}$. If it experiences a torque of $5 \times 10^{-9} \text{ Nm}$, the magnitude of the charge on the dipole is (given $\sin 30^{\circ} = 0.5$). (in $\text{ }\mu\text{C}$)

In the case of the dimensions of electric field and electric dipole moment,the power of mass is respectively:

When three electric dipoles are near each other,they each experience the electric field of the other two,and the three-dipole system has a certain potential energy. The figure below shows three arrangements $(1)$,$(2)$,and $(3)$ in which three electric dipoles are side by side. All three dipoles have the same magnitude of electric dipole moment,and the spacings between adjacent dipoles are identical. If $U_1$,$U_2$,and $U_3$ are potential energies of the arrangements $(1)$,$(2)$,and $(3)$ respectively,then:

Two parallel disks each having radius $R$ are separated by a distance $l$. The surface charge densities are $\sigma$ and $-\sigma$. The electric field at point $P$,a large distance $r$ along the axis of the disks is:

Two point masses,each of mass $m$ and charges $+q$ and $-q$,are attached to the ends of a massless rod of length $L$. This assembly is placed in a uniform electric field of intensity $E$ at a small angle $\theta$ with the field. How much time will it take for the rod to become parallel to the electric field?