2026 GS Paper I, all questions

UPSC Prelims 2026 · GS Paper I

Question 43: Science and Technology

Which of the following statements with regard to stealth technology is/are correct ?

  1. 1.Stealth objects have a very small radar cross-section and are coated with Radar Absorbing Material.
  2. 2.Stealth objects can be detected using specific frequencies.
  3. 3.Stealth objects are coated with metamaterials to increase the scattering of electromagnetic radiation.

Select the answer using the code given below :

a1 only
b2 and 3 only
c1 and 2 only
d1, 2 and 3

AnswerUPSC’s answer is (c).

Stealth technology reduces detection by shaping the object to deflect radar waves and coating it with Radar Absorbing Material, giving a very small radar cross-section. Stealth is not invisibility: radars working at specific frequencies, such as low-frequency VHF and multistatic radars, can still detect stealth objects. Metamaterials are used to absorb or redirect electromagnetic energy, not to increase scattering, so statement 3 is wrong.

  • 1. Stealth objects have a tiny radar cross-section and Radar Absorbing Material coating.
  • 2. Certain radar frequencies can still detect them.
  • 3. Metamaterials reduce or redirect scattering; they do not increase it.

How you could have got this

  1. If you were sure statement 2 is correct, (a) goes: it leaves 2 out.

    What you needed to know: Certain radar frequencies can still detect them.

  2. Then, if you were sure statement 3 is not correct, (b) and (d) go: each of them includes 3.

    What you needed to know: Metamaterials reduce or redirect scattering; they do not increase it.

Only (c) is left. You didn’t need statement 1.

This follows UPSC’s provisional key; the final key could change it.

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) Incomplete: statement 2 is also correct.
  • (b) Wrong: statement 3 is false, since stealth reduces scattering back to the radar.
  • (c) Right: small radar cross-section with absorbing coating, and detectability at specific frequencies.
  • (d) Wrong: statement 3 is false.

Only the provisional key (27 May 2026) was found; the final key replaces it when found.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2026, General Studies Paper I, Series A. The paper on upsc.gov.in.