Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: In electrostatics, a conductor does not store any net charge inside.
Reason R: Inside the capacitor (with no dielectric medium), the free charge carriers, if placed between the plates of capacitor, experience force and drift.
Choose the correct answer from the options given below

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of 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:
Evaluate the physical correctness of both the Assertion and the Reason independently. If both are factually correct physics statements, then determine if the mechanism described in the Reason is the fundamental cause producing the phenomenon described in the Assertion.
Step 2: Key Formula or Approach:
Gauss's Law inside a conductor: $E_{in} = 0 \implies Q_{in} = 0$.
Electric force on a charge: $\vec{F} = q\vec{E}$.
Step 3: Detailed Explanation:
Let's analyze Assertion (A):
In electrostatics, the electric field strictly vanishes inside the bulk material of a conductor. By Gauss's Law ($\oint \vec{E} \cdot d\vec{A} = \frac{Q_{enclosed}}{\epsilon_0}$), since $\vec{E} = 0$ everywhere inside the Gaussian surface drawn within the bulk, the net enclosed charge must be zero. Any excess charge resides entirely on the outer surface. Thus, Assertion A is true.
Let's analyze Reason (R):
Between the plates of a charged capacitor (in the vacuum gap), a uniform electric field $\vec{E}$ exists. If any free charge carrier (like an electron) is placed in this region, it will experience an electric force $\vec{F} = q\vec{E}$ and accelerate/drift towards the oppositely charged plate. Thus, Reason R is an entirely factual and true statement about electric fields acting on charges in a vacuum gap.
Relationship Check:
Does R explain A? No. Assertion A discusses the macroscopic equilibrium property of a conductive lattice (the shielding effect forcing charge to the surface so that internal fields neutralize). Reason R simply describes the trivial definition of electric force operating in an empty space between two plates. Although both involve charges moving due to forces until equilibrium, R does not explicitly explain the mechanism of surface-charge accumulation inherent to A.
Step 4: Final Answer:
Both statements are true, but R does not correctly explain A.