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Q43 (NDA-I/2015) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism Answer Verified

When you walk on a woolen carpet and bring your finger near the metallic handle of a door an electric shock is produced. This is because

Result
Your answer: —  Â·  Correct: A
Explanation

Walking on a woolen carpet generates static electricity through the triboelectric effect, where friction between different materials causes a transfer of electrons. As a person moves across the carpet, their body accumulates an excess of electric charge (electrons). Because the human body is a conductor, these charges remain on the surface until they find a path to discharge [2]. When a finger is brought near a metallic door handle—a good conductor—the accumulated static charge is rapidly transferred from the body to the handle [1]. This sudden movement of electrons, known as electrostatic discharge (ESD), creates a small spark or current flow that is perceived as an electric shock. Options involving chemical reactions or thermal equilibrium are incorrect as the phenomenon is purely electrical in nature.

Sources

  1. [2] Science-Class VII . NCERT(Revised ed 2025) > Chapter 3: Electricity: Circuits and their Components > 3.2 A Simple Electrical Circuit > p. 36
  2. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 4: The World of Metals and Non-metals > 4.1.5 Conduction of electricity > p. 48
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