Official UPSC Format

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 :

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.

⚡ Quick Recall Snippet

Stealth technology works by minimizing a vehicle's Radar Cross-Section (RCS) using geometric shaping and Radar Absorbing Materials (RAM). While stealth aircraft can evade high-frequency targeting radars, they can still be detected by specific low-frequency radars. Furthermore, advanced metamaterials are engineered to eliminate radar scattering, ensuring invisibility.

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Detailed Solution & Authority Citations

Correct Answer is Option 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.

    🚨 The Examiner's Trap

    Statement 2 plays on the myth that stealth means '100% invisible' (they can still be spotted by clunky VHF radars). Statement 3 uses a complex buzzword ('metamaterials') but flips the physics outcome ('increase' instead of 'decrease' scattering) to catch candidates who don't understand basic radar reflection.

    Active Recall Flashcard

    Tap to Flip

    In advanced stealth technology, are metamaterials designed to increase or decrease the scattering of electromagnetic radar waves?

    They are designed to decrease or eliminate scattering to prevent radar echoes.

    Concept Flow Mapping

    Stealth Technology
    Minimizes
    Radar Cross-Section
    Radar Absorbing Materials
    Dissipate
    Electromagnetic Energy
    Metamaterials
    Decrease
    Radar Scattering

    Logic Quest

    "Why does statement 3 state that increasing scattering is bad?"

    Not analyzing core concepts like Electromagnetic Manipulation in Defense through the lens of Previous Year Questions is a serious miss-out. This PYQ engine is specifically designed to help you decode the examiner's mindset and master highly probable Science & Technology questions for your upcoming Prelims.