2025 GS Paper I, all questions

UPSC Prelims 2025 · GS Paper I

Question 43: Science and Technology

In the context of electric vehicle batteries, consider the following elements :

  1. ICobalt
  2. IIGraphite
  3. IIILithium
  4. IVNickel

How many of the above usually make up battery cathodes?

aOnly one
bOnly two
cOnly three
dAll the four

AnswerThe answer is (c).

In lithium-ion batteries used in electric vehicles the cathode is a metal oxide that holds lithium. Common cathode chemistries contain lithium with nickel, cobalt, manganese or aluminium, such as NMC and NCA. Graphite is not part of the cathode: it is the usual anode material that stores lithium ions during charging. So cobalt, lithium and nickel usually make up cathodes, which is three. Remember: graphite goes on the anode side.

  • I. Cobalt is used in NMC and NCA cathodes.
  • II. Graphite is the anode material.
  • III. Lithium is part of the cathode metal oxide.
  • IV. Nickel is a main cathode metal in NMC and NCA types.

How you could have got this

No shortcut here: in a “how many” question, ruling out options doesn’t help. Every statement has to be judged.

This follows an unofficial answer: UPSC has not published its key for this year, and if that answer is wrong, so is this path.

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: three of the elements are in cathodes.
  • (b) Wrong: lithium, cobalt and nickel are all cathode materials, so two undercounts.
  • (c) Right: cobalt, lithium and nickel are cathode elements; graphite is the anode.
  • (d) Wrong: graphite is the anode material, not the cathode.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2025, General Studies Paper I, Series A. The paper on upsc.gov.in.