Electrostatics is one of the highest-weightage chapters in JEE Physics. This set covers Coulomb's law, field and potential of point charges, Gauss's law, conductors, dipoles and capacitors, with every calculation shown. Use k = 1/(4πε₀) = 9 × 10⁹ N m² C⁻².
How to practise: read each question and tap the option you think is correct. You will see right away whether you got it, along with a short explanation, and your score is tracked at the bottom of the screen. This set has 15 questions.
Topics covered in this set
- Coulomb's law and inverse-square dependence
- Electric field and potential of point charges
- Gauss's law and flux
- Conductors and equipotential surfaces
- Electric dipole in a uniform field
- Capacitors: combinations, energy and dielectrics
JEE Physics MCQs with answers and explanations
Q1. Two charges of 1 μC each are placed 1 m apart in vacuum. What is the force between them?
a) 9 × 10⁻³ N
b) 1 N
c) 9 × 10⁻⁶ N
d) 9 × 10³ N
Q2. If the distance between two point charges is halved, the electrostatic force between them becomes:
a) One quarter
b) Four times
c) Half
d) Double
Q3. What is the magnitude of the electric field 3 m from a point charge of 2 μC?
a) 6,000 N/C
b) 667 N/C
c) 18,000 N/C
d) 2,000 N/C
Q4. What is the electric potential 3 m from a point charge of 2 μC?
a) 18,000 V
b) 6,000 V
c) 667 V
d) 2,000 V
Q5. How much work is done in moving a charge between two points on the same equipotential surface?
a) qV
b) Infinite
c) Zero
d) Depends on the path
Q6. What is the electric field inside a charged conductor in electrostatic equilibrium?
a) Maximum at the centre
b) Zero
c) σ/ε₀
d) Equal to the surface field
Q7. A point charge q is placed at the centre of a cube. What is the electric flux through one face?
a) q/ε₀
b) q/6ε₀
c) Zero
d) 6q/ε₀
Q8. The separation between the plates of an air-filled parallel-plate capacitor is doubled. Its capacitance:
a) Halves
b) Doubles
c) Becomes four times
d) Stays the same
Q9. Capacitors of 2 μF and 3 μF are connected in series. What is the equivalent capacitance?
a) 5 μF
b) 1.2 μF
c) 6 μF
d) 0.83 μF
Q10. How much energy is stored in a 10 μF capacitor charged to 100 V?
a) 5 J
b) 0.5 J
c) 0.05 J
d) 0.005 J
Q11. A dielectric of constant K completely fills a parallel-plate capacitor that stays connected to a battery. What happens to the charge on the plates?
a) It stays the same
b) It increases by a factor K
c) It becomes zero
d) It decreases by a factor K
Q12. An electric dipole of moment p is placed in a uniform field E. For which angle between p and E is the torque maximum?
a) 0°
b) 45°
c) 90°
d) 180°
Q13. How does the electric field of an infinitely long uniformly charged straight wire vary with distance r?
a) ∝ 1/r
b) Independent of r
c) ∝ r
d) ∝ 1/r²
Q14. What is the electric field near an infinite plane sheet of uniform surface charge density σ?
a) σ/ε₀, decreasing with distance
b) σ/4πε₀r²
c) Zero
d) σ/2ε₀, independent of distance
Q15. Three identical capacitors of capacitance C each are connected in parallel. What is the equivalent capacitance?
a) 9C
b) C
c) 3C
d) C/3
Quick revision notes
- F = kq₁q₂/r², E = kq/r², V = kq/r, k = 9 × 10⁹.
- Total flux through a closed surface = q_enclosed/ε₀.
- E = 0 inside a conductor; field ⟂ equipotentials.
- C = ε₀A/d; series 1/C = Σ1/Cᵢ; parallel C = ΣCᵢ.
- U = ½CV²; dielectric with battery: Q ×K; isolated: V ÷K.
Frequently asked questions
Are these JEE previous year questions?
No. They are original practice questions at the JEE Main level.
What is the most common mistake in capacitor problems?
Not checking whether the battery is still connected. If it is, voltage is fixed; if not, charge is fixed.
Do I need calculus for electrostatics in JEE?
For continuous charge distributions like rings, rods and discs, yes. Learn the standard results and how they are derived.
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