This question was asked inGPSC Deputy Executive Engineer (Electrical) Class-2 Master Paper 2026Question 46 of 195 published · Gujarat Public Service CommissionOpen paper
Q46EasyElectrostatics

Consider the following statements regarding Conductors in Electrostatics:
1. Electric field inside a perfect conductor under electrostatic conditions is zero due to free charge redistribution.
2. Charges in a conductor reside only on the surface in electrostatic equilibrium.
3. Potential inside a conductor remains constant throughout its volume.
4. Electric field inside a conductor increases with depth due to induced charges.
Which of the above statements is/are correct?

Answer & step-by-step solution
Correct answer: D. 1, 2 and 3 only
Quick explanation

In electrostatic equilibrium, free charges in a conductor redistribute until the internal electric field is zero. The conductor is then an equipotential body and excess free charge resides on its surface. Key relation: Inside a perfect conductor at electrostatic equilibrium: E=0 and V=constant.

Exam focus: Zero internal E and constant potential are two views of the same equilibrium condition. Common trap: The field does not increase with depth inside an ideal conductor.

Inside a perfect conductor at electrostatic equilibrium: E=0 and V=constant.

Statement-wise Verification

  • Statement 1 - Correct.
    Electric field inside a perfect conductor under electrostatic conditions is zero due to free charge redistribution.
    In electrostatic equilibrium, free charges in a conductor redistribute until the internal electric field is zero.
  • Statement 2 - Correct.
    Charges in a conductor reside only on the surface in electrostatic equilibrium.
    In electrostatic equilibrium, free charges in a conductor redistribute until the internal electric field is zero.
  • Statement 3 - Correct.
    Potential inside a conductor remains constant throughout its volume.
    Inside a perfect conductor at electrostatic equilibrium: E=0 and V=constant.
  • Statement 4 - Incorrect.
    Electric field inside a conductor increases with depth due to induced charges.
    The correct principle is: In electrostatic equilibrium, free charges in a conductor redistribute until the internal electric field is zero.

Core Concept

In electrostatic equilibrium, free charges in a conductor redistribute until the internal electric field is zero. The conductor is then an equipotential body and excess free charge resides on its surface. If a nonzero internal field remained, free charge would continue to move, contradicting equilibrium.

Formula / Key Relationship

Inside a perfect conductor at electrostatic equilibrium: E=0 and V=constant.

Why the Other Options Are Wrong

Option A is incorrect because it omits correct statement(s) 2. Option B is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2, 3. Option C is incorrect because it omits correct statement(s) 1.

Exam Shortcut / Approach

Zero internal E and constant potential are two views of the same equilibrium condition.

Common Mistake

The field does not increase with depth inside an ideal conductor.

Quick Revision

Electrostatic Equilibrium in Conductors is linked with Conductors, Electrostatics and Electromagnetic Fields. Zero internal E and constant potential are two views of the same equilibrium condition.

Exam tipZero internal E and constant potential are two views of the same equilibrium condition.
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