UPSC Prelims 1995 · General Studies
Question 102: Science and Technology
Which one of the following polymers is widely used for making bullet-proof material?
AnswerThe answer is (d).
Polycarbonates are tough, transparent plastics that absorb a lot of impact; laminated with glass or other layers they make bullet-resistant windows and shields, and this is the polymer the given key picks. Aramid fibres, a kind of polyamide, are used in bullet-proof vests. PVC and ordinary polyethylene are not used for this. Remember: polycarbonate for transparent armour, aramids for vests.
Why each option is right or wrong
- (a) PVC is a plastic for pipes and cables, not armour.
- (b) Polyamides include aramid fibres used in vests; this is the other defensible option.
- (c) Ordinary polyethylene is soft; only special high-strength grades are used in armour.
- (d) Right per the key: polycarbonate, tough and transparent.
Worth knowing: Disputed: aramid fibres such as Kevlar are polyamides widely used in bullet-proof vests, so (b) is also defensible.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1995, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.