Three point charges +q, +2q and +Q are placed at the vertices of an equilateral triangle. If the potential energy of the system of three charges is zero, the value of Q in terms of q is

Two point charges +e and +4e are kept at a distance 'd' units apart. Third point charge +q is placed between the two charges at a distance 'x' units from charge +e so as to be in equilibrium. The value of 'x' is

Select the WRONG statement about polar molecules.

An electric dipole of length $3\text{cm}$ is placed with its axis making an angle of $60^\circ$ with a uniform electric field of $5 \times 10^4$ N/C. It experiences a torque of $9\sqrt{3}$ Nm. The magnitude of charge on the dipole is $(\sin 60^\circ = \dfrac{\sqrt{3}}{2})$