What is the electrostatic force between two point charges q1 and q2 separated by distance r in vacuum (Coulomb's Law)?
Answer and explanation
Correct answer: D. F = q1 q2 / (4 pi epsilon_0 r^2)
- Step 1: Coulomb's inverse square law states force is proportional to product of charges and inversely proportional to r^2. Step 2. In SI units, the constant of proportionality is 1 / (4 pi epsilon_0). Answer: F = q1 q2 / (4 pi epsilon_0 r^2). Why not the others: Linear r has wrong dimensions; multiplying 4 pi epsilon_0 inverts permittivity; 2 pi is for cylindrical line charge.
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