Coulomb force

A conducting spherical shell is earthed. A positive charge $q_1$ is placed at the center and another small positive charge $q_2$ is placed at a distance $r$ from $q_1$ . Ignore the effect of induced charge due to $q_2$ on the sphere. Then find the coulomb force on $q_2$ .

Given: $q_1 = 1\text{ C} , q_2 = 2\text{ C}, r = 1\text{ m} , R = 25 \text{ cm}$ .