UPSC Prelims 2023 · GS Paper I
Question 53: Science and Technology
Consider the following statements :
- 1.Carbon fibres are used in the manufacture of components used in automobiles and aircrafts.
- 2.Carbon fibres once used cannot be recycled.
Which of the statements given above is/are correct?
AnswerUPSC’s answer is (a).
Carbon fibres are strong, light and stiff, so composites made from them are used for automobile and aircraft parts as well as sports goods and wind-turbine blades; statement 1 is correct. Statement 2 is wrong: carbon fibre composites can be recycled by pyrolysis, solvolysis or mechanical processes that recover the fibres for reuse, though recovered fibre is usually shorter and lower-grade.
- 1. Carbon fibre composites are used in automobiles and aircraft.
- 2. Carbon fibres can be recovered and recycled.
How you could have got this
- If you were sure statement 1 is correct, (b) and (d) go: each of them leaves 1 out.
What you needed to know: Carbon fibre composites are used in automobiles and aircraft.
- Then, if you were sure statement 2 is not correct, (c) goes: it includes 2.
What you needed to know: Carbon fibres can be recovered and recycled.
Only (a) is left. This one needs every statement.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Correct: only statement 1 is true.
- (b) Statement 2 is false because carbon fibre can be recycled.
- (c) Statement 2 is false, so not both.
- (d) Statement 1 is true, so not neither.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2023, General Studies Paper I, Series A. The paper on upsc.gov.in.