Coulomb’s Law Numerical MCQs for Class 12 Physics
Coulomb’s Law Numerical MCQs – Class 12 Physics
Class: 12 | Subject: Physics |
Section: Electrostatics |
Topic: Coulomb’s Law Numerical MCQs
Based on: NCERT Syllabus | CBSE Board Examination Standard
Based on: NCERT Syllabus | CBSE Board Examination Standard
Instructions: These Multiple Choice Questions (MCQs) are designed strictly as per the NCERT syllabus, making them ideal for CBSE Class 12 Board Examination preparation.
1. Two charges 2 μC each are placed 1 m apart. Force between them is:
Answer: B
F = kq²/r² = 9×10⁹ × (2×10⁻⁶)² = 0.036 N.
F = kq²/r² = 9×10⁹ × (2×10⁻⁶)² = 0.036 N.
2. If distance doubles, force becomes:
Answer: C
F ∝ 1/r² → doubling r makes force 1/4.
F ∝ 1/r² → doubling r makes force 1/4.
3. Force between 1 μC and 2 μC at 0.5 m:
Answer: B
F = 9×10⁹ × 2×10⁻¹² / 0.25 = 0.072 N.
F = 9×10⁹ × 2×10⁻¹² / 0.25 = 0.072 N.
4. Medium dielectric constant 4 → force becomes:
Answer: C
F = Fair/K.
F = Fair/K.
5. Ratio of forces when charge doubles:
Answer: D
F ∝ q₁q₂ → doubling both → 4 times.
F ∝ q₁q₂ → doubling both → 4 times.
6. Unit of Coulomb constant k:
Answer: A
k = 9×10⁹ N m² C⁻².
k = 9×10⁹ N m² C⁻².
7. Force between unlike charges is:
Answer: B
Opposite charges attract.
Opposite charges attract.
8. If one charge is zero, force is:
Answer: C
F ∝ q₁q₂.
F ∝ q₁q₂.
9. Force direction is along:
Answer: C
Acts along line joining charges.
Acts along line joining charges.
10. k value depends on:
Answer: A
k = 1/4πϵ.
k = 1/4πϵ.
11. Permittivity unit:
Answer: A
From Coulomb law formula.
From Coulomb law formula.
12. Superposition principle applies to:
Answer: B
Net force = vector sum.
Net force = vector sum.
13. Three charges in line → net force found by:
Answer: B
Forces add vectorially.
Forces add vectorially.
14. Force ∝ permittivity relation:
Answer: B
F ∝ 1/ϵ.
F ∝ 1/ϵ.
15. If medium removed, force:
Answer: B
Air → higher force.
Air → higher force.
16. Force between electrons is:
Answer: B
Like charges repel.
Like charges repel.
17. Law valid for charges:
Answer: A
Electrostatics → stationary charges.
Electrostatics → stationary charges.
18. Force graph vs distance:
Answer: C
F ∝ 1/r² curve.
F ∝ 1/r² curve.
19. S.I. unit of charge:
Answer: B
Standard SI unit.
Standard SI unit.
20. Force becomes zero when charges are:
Answer: C
At infinite separation force → 0.
At infinite separation force → 0.