Two identical conducting spheres carry positive charges $q_1$ and $q_2$ ($q_1 \ne q_2$) and repel with force $F$ at separation $r$. They are touched together and returned to the same separation $r$. The new force is

1. On contact identical spheres share charge equally: each becomes $\dfrac{q_1+q_2}{2}$. 2. New force $\propto \left(\dfrac{q_1+q_2}{2}\right)^2$; old force $\propto q_1q_2$. 3. By AM–GM, $\left(\dfrac{q_1+q_2}{2}\right)^2 > q_1q_2$ whenever $q_1\ne q_2$, so the force is **greater than before**. _Source: Samacheer Kalvi Class 12 Physics Vol.1, Unit 1 'Electrostatics', Evaluation Q.7 (NSEP)_