There are two thin wire rings, each of radius $R$, whose axes coincide. The charges of the rings are $q$ and $-q$. The magnitude of potential difference between the centres of the rings separated by a distance $\sqrt{3} R$ is

Two charged particles of mass 1 g each are placed 1 m apart. If each of these possesses 1 femto coulomb of charge, then the dominant force of interaction between them is

Three charges are arranged on the vertices of a right angle triangle as shown in the figure. The magnitude of dipole moment of the combination in the unit of $\mathrm{C}-\mathrm{cm}$ is

A particle of mass $m$ and charge $q$ travelling with a velocity $v$ along the $X$-axis enters a uniform electric field $\mathbf{E}$ directed along the $Y$-axis. What will be the trajectory of the particle?