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 :

Both (A) and (R) are correct and (R) is the correct explanation of (A)

Both (A) and (R) are correct but (R) is not the correct explanation of (A)

(A) is correct but (R) is not correct

(A) is not correct but (R) is correct

Electrostatics PYQ — JEE Main 2025 · 7 Apr · Shift 2 · Q61 with Solution

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Correct answer: C

Understand the assertion

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

This is correct. A metal body acts like a conducting enclosure. When lightning strikes, charge flows over the outer surface of the conductor, and the inside remains protected. This is the principle of electrostatic shielding or a Faraday cage.
Understand the reason

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

This is also correct in electrostatic equilibrium. For a closed conductor, $E=0$ inside the conducting material, and the electric field inside an enclosed cavity is zero provided no charge is placed inside the cavity.
Check whether the reason explains the assertion

In an aircraft, the metallic outer body forms a conducting shell. During a lightning strike, charges redistribute on the outer surface so that the electric field inside is zero. Therefore, passengers inside are protected.

So, the reason directly explains the assertion.
Evaluate the options
- A: Both are correct, but R is not the correct explanation of A → Incorrect
- B: A is correct, but R is not correct → Incorrect
- C: Both A and R are correct, and R is the correct explanation of A → Correct
- D: A is not correct, but R is correct → Incorrect
Final answer

The correct option is: $\boxed{C}$

View written solutionFree

Correct answer: C

Understand the assertion

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

This is correct. A metal body acts like a conducting enclosure. When lightning strikes, charge flows over the outer surface of the conductor, and the inside remains protected. This is the principle of electrostatic shielding or a Faraday cage.
Understand the reason

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

This is also correct in electrostatic equilibrium. For a closed conductor, $E=0$ inside the conducting material, and the electric field inside an enclosed cavity is zero provided no charge is placed inside the cavity.
Check whether the reason explains the assertion

In an aircraft, the metallic outer body forms a conducting shell. During a lightning strike, charges redistribute on the outer surface so that the electric field inside is zero. Therefore, passengers inside are protected.

So, the reason directly explains the assertion.
Evaluate the options
- A: Both are correct, but R is not the correct explanation of A → Incorrect
- B: A is correct, but R is not correct → Incorrect
- C: Both A and R are correct, and R is the correct explanation of A → Correct
- D: A is not correct, but R is correct → Incorrect
Final answer

The correct option is: $\boxed{C}$