UPSC Prelims 2026 Question:

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 : 

Answer: 3 

Explanation:  

Stealth technology is used to reduce the detectability of aircraft, ships, missiles or other platforms by radar,  infrared, acoustic and other detection systems. It does not make an object completely invisible; rather, it reduces  the probability of detection or delays detection. Radar stealth mainly depends on shaping, radar-absorbing  materials and reduction of radar cross-section. 

• Stealth objects are designed to have a very small radar cross-section. Their shape deflects radar waves  away from the receiver, and they may also be coated with Radar Absorbing Material to absorb part of  the incident electromagnetic energy. So, statement 1 is correct. 
• Stealth objects can still be detected under certain conditions. Low-frequency radars, multi-static radars,  passive sensors and other specialised detection systems may detect or track stealth platforms, although  often with reduced accuracy. So, statement 2 is correct. 
• Stealth objects are not coated with metamaterials to increase the scattering of electromagnetic  radiation. The objective of stealth coatings and advanced materials is to reduce reflection, scattering or  detectability, not to increase scattering. So, statement 3 is not correct. 

Therefore, option (3) is the correct answer.