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 $(\sin 60^\circ = \dfrac{\sqrt{3}}{2})$

Two spherical hollow spheres of radii '$R_1$' and '$R_2$' are charged with same charge. Let '$\sigma_1$' and '$\sigma_2$' are their respective charge densities, then the ratio $\sigma_1$ to $\sigma_2$ is