Assertion and Reason on Electric Field in a Conductor Cavity – Rankers Physics

Electric Field: Practice Problem & Solution

Assertion (A): Electric field is always zero in a cavity inside a conductor. Reason (R): All points in a cavity inside a conductor are always at same potential.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Electric Field. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is true for an uncharged cavity in electrostatic equilibrium (electrostatic shielding). Reason (R) is also true, as \(\vec{E} = -\nabla V\), so zero field implies constant potential. However, constant potential is a consequence of zero field, not its explanation.

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