Two identical small beads each have mass m and charge q. When placed in a hemispherical bowl of radius R with frictionless, non-conductive walls, the beads move and at equilibrium the line joining the beads is horizontal and the distance between them is R (see figure). Neglect any induced charge on the hemispherical bowl. Then the charge on each bead is $(\mathrm{here} \left.\mathrm{K}=\frac{1}{4{\mathrm{\pi \epsilon }}_0}\right)$