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Q8 (NDA-II/2015) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism Answer Verified

Lightning conductors are used to protect building from lightning strikes. Which of the following statements is / are true about lightning conductors? 1. Lightning conductors create an electric field at its top so that lightning strikes it preferentially 2. Li ghtni ng conductors reduce the effect of the strike by uniformly distributing the charge (current) over the surface of the building 3. Lightning conductors take all charge (current) to deep down in the earth 4. Lightning conductors must be installed at a place taller than the building Select the correct answer using the code given below:

Result
Your answer: —  Â·  Correct: C
Explanation

Lightning conductors are metallic rods installed higher than the highest point of a building [2]. Statement 1 is true because the pointed tip of the rod ionizes the surrounding air, creating an electric field that provides a pathway of least resistance, ensuring lightning strikes it preferentially. Statement 2 is false; lightning conductors do not distribute charge over the building's surface but rather provide a specific, low-resistance path to ground to prevent current from flowing through the structure itself [1]. Statement 3 is true as the system is designed to carry the entire lightning current deep into the earth via buried earthing rods [1]. Statement 4 is true because the rod must be the tallest point to effectively intercept the strike before it hits the building [2]. Thus, statements 1, 3, and 4 are correct.

Sources

  1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 6: Pressure, Winds, Storms, and Cyclones > Ever heard of ... > p. 92
  2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 25: Thunderstorm > Lightning From Cloud To Earth > p. 349
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