OPSC OAS 2020 PrelimsScience & TechnologyQuestion 19
Solved previous year question from the OPSC OAS/OCS 2020 Preliminary Examination (General Studies), with the official answer key and a detailed explanation.
Question
Which of the following substances is not synthetic?
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Answer & Explanation
Correct answer: (A) Fibroin
- Fibroin is NOT a synthetic substance. It is a naturally occurring protein produced by silkworms and spiders.
- Fibroin is the primary structural protein of silk fibre, making up approximately 70-80% of silk thread. It is produced by the silkworm Bombyx mori during the formation of its cocoon.
The other options are synthetic
| Substance | Type | Details |
|---|---|---|
| (B) Lexan | Synthetic polymer | A brand name for polycarbonate plastic. Extremely strong, transparent, impact-resistant. Used in bulletproof glass, eyeglass lenses, CDs/DVDs, aircraft windows, safety helmets. |
| (C) Neoprene | Synthetic rubber | Also called polychloroprene. Developed by DuPont in 1930. Resistant to oil, heat, and weathering. Used in wetsuits, laptop sleeves, gaskets, hoses, electrical insulation. |
| (D) Teflon | Synthetic polymer | Chemically Polytetrafluoroethylene (PTFE). Discovered by Roy Plunkett in 1938. Known for its non-stick properties, chemical inertness, and heat resistance. Used in non-stick cookware, electrical insulation, medical devices, aerospace applications. |
