Official Question UPSC 2026
Which of the following statements with regard to stealth technology is/are correct ? 1. Stealth objects have a very small radar cross-section and are coated with Radar Absorbing Material. 2. Stealth objects can be detected using specific frequencies. 3. Stealth objects are coated with metamaterials to increase the scattering of electromagnetic radiation. Select the answer using the code given below :
Solution & Analysis
Answer: C
Let us evaluate the physics of Low-Observable (Stealth) Technology:
•Statement 1 is Correct: The fundamental objective of stealth is to shrink the object's Radar Cross-Section (RCS)—how large it appears to a radar receiver. This is done by shaping the aircraft with flat surfaces to deflect radar waves away, and coating it in Radar Absorbing Materials (RAM), which soak up electromagnetic energy and dissipate it as heat.
•Statement 2 is Correct: "Stealth" does not equal "invisible." While optimized to defeat high-frequency (X-band) targeting radars, stealth aircraft are often physically large enough to resonate with the long wavelengths of low-frequency radars (VHF/UHF bands). Thus, they can be broadly detected by specific low frequencies, though these radars lack the precision for a missile lock.
•Statement 3 is Incorrect: Radar detects objects by listening for "scattered" waves bouncing back. Metamaterials are highly advanced, engineered structures. In stealth, they are deployed specifically to decrease or entirely eliminate scattering (by perfectly absorbing or bending waves around the object). Increasing scattering would have the opposite effect, making the aircraft highly visible.
Conclusion: Statements 1 and 2 accurately reflect radar physics.