UPSC Prelims 2023 Q53: Science & Technology – Materials & Engineering
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (a) 1 only
Explanation
Carbon Fibres — Properties and Recyclability
| Statement | Claim | Verdict | Detail |
|---|---|---|---|
| 1 | Carbon fibres used in automobiles and aircraft components | TRUE | Carbon fibre reinforced polymer (CFRP) is widely used in aerospace (Boeing 787, Airbus A350 — ~50% CFRP by weight) and automotive industries (Formula 1, BMW i-series, sports cars) for high strength-to-weight ratio. |
| 2 | Carbon fibres once used cannot be recycled | FALSE | Carbon fibres CAN be recycled — though it is technically challenging. Methods include: |
- Pyrolysis (thermal decomposition)
- Chemical solvolysis
Recycled carbon fibres have slightly lower mechanical properties than virgin fibres but are increasingly used in secondary applications. The statement is factually incorrect.
Answer: (a) 1 only.
Why each option is right or wrong
- (a) CORRECT. Statement 1 is correct (CFRP is used in automobiles and aircraft). Statement 2 is incorrect (carbon fibres can be recycled through pyrolysis and chemical methods).
- (b) Incorrect. Statement 2 alone being correct would mean CFRP is not used in vehicles — but it is a core aerospace and automotive material.
- (c) Incorrect. 'Both 1 and 2' — Statement 2 is false; carbon fibre recycling is an active and growing industrial process.
- (d) Incorrect. 'Neither' — Statement 1 is clearly correct; CFRP is fundamental to modern aerospace and high-performance automotive manufacturing.
Key point
Carbon fibres ARE used in automobiles and aircraft (CFRP). Carbon fibres CAN be recycled (pyrolysis, solvolysis) — though properties degrade somewhat. Statement 2 (cannot be recycled) is FALSE.
Remember
Carbon fibres are used in automobile and aircraft components (Statement 1 is correct). Carbon fibres can be recycled through pyrolysis and chemical methods (Statement 2 is false — they CAN be recycled).
Common mistakes
- Assuming carbon fibres are non-recyclable because they seem exotic — recycling technology for CFRP has advanced significantly for sustainability purposes.
- Not knowing CFRP's aerospace dominance — Boeing 787 Dreamliner uses ~50% composites (mostly CFRP) — a landmark in aviation materials.
- Thinking 'high-performance material = non-recyclable' — recyclability is about processing chemistry, not performance level.
Exam tip
CFRP = aerospace + automotive ✓. Carbon fibre recyclable = YES (pyrolysis/chemical) ✓. The 'cannot be recycled' statement is the trap. As sustainability becomes critical, carbon fibre recycling is a growing industry — UPSC tests this current awareness.
Sources
- NCERT Science — Advanced Materials
- European Commission — Carbon Fibre Recycling Research