NDA General Ability Question (2026) — Solution

Step-by-step solution

A lightning rod has a sharp tip, which means the radius of curvature at the tip is very small. Since surface charge density is inversely proportional to the radius of curvature, the charge density at the sharp tip becomes very high. The electric field near the surface of a conductor is given by E = _0 . Thus, the intense charge density creates a very strong local electric field. This strong electric field ionizes the surrounding air molecules, leading to a continuous corona discharge. This discharge helps in partially neutralizing the charge of the cloud and provides a conducting path for the lightning to safely reach the ground, thereby reducing the risk of damage. Answer: It enhances field and promotes continuous corona discharge.