Electrostatics is one of 9 topics in the Grade 11 Physical Sciences CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. Coulomb's Law states that the electrostatic force between two point charges is:
Directly proportional to the product of the charges and inversely proportional to the square of the distance between them
Directly proportional to the distance between them
Inversely proportional to the product of the charges
Independent of the distance between them
Answer: Directly proportional to the product of the charges and inversely proportional to the square of the distance between them — Coulomb's Law: F = kQ1Q2/r^2, an inverse-square law, directly proportional to the product of the charge magnitudes.
Easy
2. Two charges of the same sign (both positive, or both negative) will:
Repel each other
Attract each other
Exert no force on each other
Only exert a force if they are touching
Answer: Repel each other — Like charges (same sign) repel each other; unlike charges (opposite signs) attract each other.
Medium
3. Two point charges of 2 x 10^-6 C and 3 x 10^-6 C are 0,3 m apart. Using k = 9 x 10^9 N.m^2.C^-2, calculate the magnitude of the force between them, in newtons.
Answer: 0.6 — F = kQ1Q2/r^2 = (9x10^9 x 2x10^-6 x 3x10^-6)/(0,3)^2 = (9x10^9 x 6x10^-12)/0,09 = 0,054/0,09 = 0,6 N.
