WAEC Physics 2020 Paper

Concept:The electric force between two charges depends on the magnitudes of the charges and the distance between them, not on their masses.Explanation:Coulomb's law states: $F = k\frac{q_1 q_2}{r^2}$.Here, $q_1$ and $q_2$ are the charges, $r$ is the distance between them, and $k$ is a constant.For two positively charged particles, $q_1$ and $q_2$ are both positive and unchanged.Since $F$ is inversely proportional to $r^2$, decreasing the distance $r$ will increase the electric force $F$.Mass does not appear in Coulomb's law, so changing the mass has no effect on the electric force.Therefore, the force increases when the particles are brought closer together.Answer:B. Decreasing the distance between the particles