Electric Charges & Fields MCQs Class 12 Physics
Electric Charges & Fields MCQs
Class: 12
Subject: Physics
Section: Electrostatics
Topic: Electric Charges & Fields
Board: CBSE Board Examinations
Subject: Physics
Section: Electrostatics
Topic: Electric Charges & Fields
Board: CBSE Board Examinations
Instructions: These Multiple Choice Questions (MCQs) are designed strictly as per the NCERT syllabus, making them ideal for CBSE Class 12 Board Examination preparation.
Q1. The SI unit of electric charge is:
Answer: B) Coulomb
Explanation: Electric charge is measured in coulomb (C). One coulomb equals the charge transported by a current of 1 ampere in 1 second.
Explanation: Electric charge is measured in coulomb (C). One coulomb equals the charge transported by a current of 1 ampere in 1 second.
Q2. Like charges:
Answer: B) Repel
Explanation: According to Coulomb’s law, charges of same nature exert repulsive force on each other.
Explanation: According to Coulomb’s law, charges of same nature exert repulsive force on each other.
Q3. Coulomb’s law is valid for:
Answer: A) Point charges
Explanation: Coulomb’s law strictly applies to point charges or spherically symmetric charge distributions.
Explanation: Coulomb’s law strictly applies to point charges or spherically symmetric charge distributions.
Q4. The force between two charges varies inversely with:
Answer: B) r²
Explanation: From Coulomb’s law: F ∝ 1/r².
Explanation: From Coulomb’s law: F ∝ 1/r².
Q5. Electric field is a:
Answer: B) Vector
Explanation: Electric field has both magnitude and direction, hence vector.
Explanation: Electric field has both magnitude and direction, hence vector.
Q6. Electric field lines originate from:
Answer: B) Positive charge
Explanation: Field lines start from positive and end on negative charges.
Explanation: Field lines start from positive and end on negative charges.
Q7. The permittivity of free space is:
Answer: A) 8.85×10⁻¹² F/m
Explanation: It is denoted by ε₀ and appears in Coulomb’s law.
Explanation: It is denoted by ε₀ and appears in Coulomb’s law.
Q8. Electric field inside a conductor is:
Answer: B) Zero
Explanation: Free charges rearrange to cancel internal field.
Explanation: Free charges rearrange to cancel internal field.
Q9. Charge is quantized in units of:
Answer: A) e
Explanation: e = 1.6×10⁻¹⁹ C is the fundamental charge.
Explanation: e = 1.6×10⁻¹⁹ C is the fundamental charge.
Q10. Superposition principle applies to:
Answer: C) Both
Explanation: Net force/field equals vector sum of individual effects.
Explanation: Net force/field equals vector sum of individual effects.
Q11. Unit of electric field:
Answer: A) N/C
Electric field = Force/Charge.
Electric field = Force/Charge.
Q12. Field lines never:
Answer: C) Intersect
Intersection would give two directions of field.
Intersection would give two directions of field.
Q13. Electric flux depends on:
Answer: A) Charge enclosed
From Gauss’s law.
From Gauss’s law.
Q14. Number of field lines indicates:
Answer: A) Charge magnitude
Q15. Smallest charge observed:
Answer: B) Electron
Magnitude equals elementary charge e.
Magnitude equals elementary charge e.
Q16. Electric field at center of charged ring:
Answer: A) Zero
Symmetry cancels field.
Symmetry cancels field.
Q17. Direction of field due to negative charge:
Answer: B) Inward
Q18. Force between charges in medium decreases due to:
Answer: A) Permittivity
Q19. Charge on conductor resides on:
Answer: A) Surface
Q20. Gauss law relates flux with:
Answer: A) Charge enclosed
Φ = Q/ε₀.
Φ = Q/ε₀.