The electric dipole is situated in an electric field as shown in figure $(i)$. The dipole and electric field are both in the plane of the paper. The dipole is rotated about an axis perpendicular to the paper at point $A$ in an anticlockwise direction. If the angle of rotation is measured with respect to the direction of the electric field,then the torque for different values of the angle of rotation $\theta$ will be as represented in Fig. $(ii)$.

What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line? $(...^o)$

Two charged particles each of mass $9.8 \text{ g}$ and charges $+20 \mu\text{C}$ and $-20 \mu\text{C}$ are attached to the two ends of a massless and rigid uniform non-conducting rod of length $50 \text{ cm}$. This arrangement is held in a uniform electric field of $12.1 \text{ N/C}$,such that the rod makes a very small angle with the field direction. If the rod is set free,the minimum time needed for the rod to become parallel to the direction of the electric field is ................ seconds.

An electric dipole is placed in a uniform electric field $\vec{E}$ of magnitude $40\ N/C$. The graph shows the magnitude of the torque $\tau$ on the dipole versus the angle $\theta$ between the field $\vec{E}$ and the dipole moment $\vec{p}$. The magnitude of the dipole moment $\vec{p}$ is equal to:

An electric dipole is placed in a non-uniform electric field. Then,net

Two charges $+q$ and $-q$ are placed at a distance $b$ apart as shown in the figure. The electric field at a point $P$ on the perpendicular bisector as shown is