Question

Assertion (A): Free charge cannot exist inside a conductor.
Reason (R): If a free charge is kept between the plates of a capacitor, then it will experience force and it will drift.

• A. A & R both correct and R explains A.
• B. A & R both correct and R does not explain A.
• C. A is true but R is false.
• D. A is false but R is true

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Assertion (A) relates to the electrostatic properties of a conductor. In electrostatic equilibrium, the electric field inside a conductor is zero, which means any net charge must reside on the surface. Reason (R) relates to the behavior of a charge in an external electric field, such as that within a capacitor.

Step 2: Key Formula or Approach:
1. Gauss's Law: \( \oint E \cdot dA = \frac{q_{in}}{\epsilon_0} \). Since \( E = 0 \) inside a conductor, \( q_{in} = 0 \). 2. Force on a charge: \( F = qE \).

Step 3: Detailed Explanation:
- Assertion (A): In a conductor, charges are free to move. If there were an internal electric field, charges would move until the field becomes zero. By Gauss's Law, if \( E=0 \), the net internal charge is zero. Thus, (A) is true.
- Reason (R): Between the plates of a capacitor, there is a uniform electric field \( E \). A free charge \( q \) experiences a force \( F=qE \) and will move (drift) in the direction of the field. Thus, (R) is true.
- Explanation Check: While both are true statements regarding the behavior of free charges, the drifting of a charge in a capacitor does not explain why net charge cannot exist inside a bulk conductor in equilibrium. The latter is due to electrostatic shielding and repulsion.

Step 4: Final Answer:
Both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.