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  9. Q125

JPSC 2021 · Question 125 of 198

Light Emitting Diode (LED) work on principle of

Physics

  1. AElectroluminescenceCorrect
  2. BLaser
  3. CThermionic emission
  4. DPhotoelectric code

Answer: A. Electroluminescence

Explanation

An LED emits light when charge carriers recombine in a semiconductor - electroluminescence.

Source: JPSC Combined Civil Services (PT) 2021 (Advt 01/2021, held 19 Sep 2021), GS Paper-I (General Studies), Booklet Series-A; answers per official REVISED answer key (published 08 Oct 2021 on jpsc.gov.in, via JagranJosh), each cross-checked against factual records; Paper-I Q27.

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