Question

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:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. (A) is correct but (R) is not correct
• C. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• D. (A) is not correct but (R) is correct

Hint:

In electrostatics, the electric field inside a conductor is always zero in electrostatic equilibrium. This concept is used in Faraday cages and aircraft protection against lightning strikes.

Answer 1

The Correct Option is A

Step 1: Understanding Assertion (A)
The outer body of an aircraft is made of metal, which provides a conductive path for electric charge to flow. In case of lightning strikes, the metal body of the aircraft channels the electrical current around the passengers, preventing it from entering the interior. This is why passengers are safe inside a metal-bodied aircraft during lightning strikes. 
Therefore, assertion (A) is correct. 

Step 2: Understanding Reason (R)
The electric field inside a conductor in electrostatic equilibrium is zero. This is known as the principle of electrostatic shielding. When an external electric field is applied, the free charges in the conductor rearrange themselves to cancel the electric field inside the conductor. 
Therefore, reason (R) is also correct. 

Step 3: Connecting Assertion and Reason
The metal body of the aircraft behaves as a conductor. According to the principle of electrostatic shielding, the electric field inside the conducting body (the aircraft) is zero, which protects the passengers from the effects of lightning strikes. 
Thus, reason (R) explains why assertion (A) is true.