Two point charges q1 and q2 exert a force F on each other. If the value of q1 is doubled while q2 and the separation r stay fixed, what happens to the force F?

1. Coulomb's law states that F is proportional to the product q1 q2, not to either charge squared. 2. Doubling q1 while holding q2 and r fixed doubles the product q1 q2. 3. Since F is directly proportional to that product, F also doubles. 4. Quadrupling only happens if the distance is halved, since distance enters as an inverse square, so option D mixes up the charge and distance dependence, which is the trap to watch for when scaling Coulomb's law. _Source: OpenStax Physics (CC BY 4.0), Ch 18 "Static Electricity", section 18.2 Coulomb's law_