Easy MCQ +4 / -1 PYQ · JEE Mains 2025

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : The outer body of an aircraft is made of metal which protects persons sitting inside from lightning strikes.

Reason (R) : The electric field inside the cavity enclosed by a conductor is zero.

In the light of the above statements, choose the most appropriate answer from the options given below :

  1. A <p>Both (A) and (R) are correct but (R) is not the correct explanation of (A)</p>
  2. B <p>(A) is correct but (R) is not correct</p>
  3. C <p>Both (A) and (R) are correct and (R) is the correct explanation of (A)</p> Correct answer
  4. D <p>(A) is not correct but (R) is correct</p>

Solution

<p>The assertion suggests that the outer body of an aircraft is made of metal to protect passengers from lightning strikes. The reason provided is that the electric field inside a cavity enclosed by a conductor is zero. </p> <p>This reasoning is based on the property of metallic conductors, where the electric field within a conductor's cavity is indeed zero. This phenomenon occurs because the charges on a conductor redistribute themselves to cancel any external electric fields within the conductor. Thus, if lightning were to strike an aircraft, the metal body would direct the electric charges along its surface, effectively shielding the interior where passengers are located. </p> <p>Therefore, the assertion and the reason are both correct, and the reason correctly explains why the metal body of an aircraft shields passengers from lightning. This aligns with the principles of electromagnetic shielding. The key point is that the conductive nature of the aircraft’s metal body ensures no electric field permeates the interior, keeping passengers safe.</p>

About this question

Subject: Physics · Chapter: Electrostatics · Topic: Electric Field and Field Lines

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