UPSC Prelims 2022 · GS Paper I
Question 98: Science and Technology
Consider the following statements :
- 1.Other than those made by humans, nanoparticles do not exist in nature.
- 2.Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.
- 3.Nanoparticles of some commercial products which enter the environment are unsafe for humans.
Which of the statements given above is/are correct ?
AnswerUPSC’s answer is (d).
Nanoparticles occur naturally, for example in volcanic ash, sea spray, dust and smoke, so statement 1 is wrong. Nano-sized metal oxides such as titanium dioxide and zinc oxide are used in sunscreens and cosmetics. Some engineered nanoparticles that enter the environment can be toxic to humans and other organisms. So statements 2 and 3 are correct.
- 1. Nanoparticles also occur naturally, as in volcanic ash and sea spray.
- 2. Nano-sized metal oxides are used in some cosmetics.
- 3. Some nanoparticles that enter the environment are unsafe for humans.
How you could have got this
- If you were sure statement 1 is not correct, (a) and (c) go: each of them includes 1.
What you needed to know: Nanoparticles also occur naturally, as in volcanic ash and sea spray.
- Then, if you were sure statement 2 is correct, (b) goes: it leaves 2 out.
What you needed to know: Nano-sized metal oxides are used in some cosmetics.
Only (d) is left. You didn’t need statement 3.
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) Wrong. Natural nanoparticles exist, so statement 1 is false.
- (b) Wrong. Statement 2 on cosmetics is also correct.
- (c) Wrong. Statement 1 is false.
- (d) Correct. Cosmetics use metal-oxide nanoparticles, and some are unsafe.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2022, General Studies Paper I, Series A. The paper on upsc.gov.in.