1. Concept: According to Coulomb's Law, the electrostatic force between two particles depends exclusively on the magnitude of their charges and the distance between them, entirely independent of their masses.
2. Formula: $$ F = \frac{k q_1 q_2}{r^2} $$
3. Solution: - The charge of a proton is \( +e \) and the charge of an electron is \( -e \). They share the identical charge magnitude (\( 1.6 \times 10^{-19} \text{ C} \)).
- At a fixed distance \( r \), the force between two protons is \( F_p = \frac{k e^2}{r^2} \).
- At the same distance, the force between two electrons is \( F_e = \frac{k e^2}{r^2} \).
- The ratio \( F_p / F_e \) is exactly 1.
4. Why other options are incorrect: Options A, B, and C attempt to bait students into confusing the ratio of electrostatic force with the ratio of
gravitational vs electrostatic force, which scales with mass and leads to large exponents like \( 10^{39} \).
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