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Q39 (NDA-I/2021) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism Answer Verified

LED (a semi-conductor device) is an abbreviation that stands for

Result
Your answer: —  Â·  Correct: C
Explanation

The abbreviation LED stands for Light Emitting Diode [2]. It is a solid-state semiconductor device that converts electrical energy directly into light energy [3]. Structurally, an LED is a diode that allows electric current to flow in only one direction [3]. When a voltage is applied and current flows through the semiconductor material, electrons recombine with electron holes, releasing energy in the form of photons (light) [4]. This process is known as electroluminescence. Compared to traditional incandescent lamps, LEDs are significantly more energy-efficient, consume less power, and have a much longer operational lifespan [1]. Because of these advantages, they are widely used in modern lighting applications, including torches, household bulbs, and electronic displays [2].

Sources

  1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 11: Light: Shadows and Reflections > SCIENCE AND SOCIETY > p. 154
  2. [2] https://www.sciencedirect.com/topics/physics-and-astronomy/light-emitting-diode
  3. [3] Science-Class VII . NCERT(Revised ed 2025) > Chapter 3: Electricity: Circuits and their Components > In a Nutshell > p. 37
  4. [4] https://en.wikipedia.org/wiki/Light-emitting_diode_physics
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