UPSC CSE Prelims
Naval, Air and Land Defence Technologies Previous Year Questions (PYQs)

Detailed Explanation:

CL-20, HMX, and LLM-105 are advanced high-energy explosive compounds used in military applications.

• CL-20 is one of the most powerful non-nuclear explosives developed.

• HMX is widely used in missiles, warheads, and other military munitions.

• LLM-105 is a modern explosive known for its high performance and improved thermal stability.

• Therefore, all three are explosives used in military weapons, making Option B the correct answer.

Why Other Options Are Wrong

Detailed Explanation:

Correct Answer: ✅ Only Two (Option B)

Radar works by transmitting radio waves and detecting their reflected signals from objects. It is widely used in weather monitoring and wildlife tracking, but not for identifying narcotics on passengers.

❌ Statement I is Incorrect: Narcotics detection at airports is generally done using X-ray scanners, trace detectors, sniffer dogs, and chemical analysis, not radar.

✅ Statement II is Correct: Weather radars are extensively used to monitor precipitation such as rain, snow, and storms.

✅ Statement III is Correct: Radar technology is used to track the migration of birds, bats, and other animals for ecological studies.

Short Notes: Radar Applications

• RADAR stands for Radio Detection And Ranging.

• It uses radio waves to detect the location, speed, and direction of objects.

• Weather radars monitor rainfall, thunderstorms, and cyclones.

• Doppler Radar can measure the velocity of moving objects.

• Radar is widely used in aviation, defense, navigation, and meteorology.

• It helps track bird and animal migration over long distances.

• Radar works effectively in darkness, fog, and cloudy conditions.

Detailed Explanation:

Correct Answer: ✅ Option 4 (None)

Fifth-generation fighter aircraft are characterized by stealth technology, sensor fusion, supercruise capability, advanced avionics, and network-centric warfare systems. None of the aircraft listed belong to the fifth-generation category.

❌ Rafale – Incorrect: The Dassault Rafale is a 4.5-generation multirole fighter aircraft developed by France.

❌ MiG-29 – Incorrect: The Mikoyan MiG-29 is a fourth-generation fighter aircraft.

❌ Tejas MK-1 – Incorrect: The HAL Tejas Mk1 is generally classified as a fourth-generation light combat aircraft with some modern upgrades.

Therefore, none of the above are fifth-generation fighter aircraft.

Short Notes: Fighter Aircraft Generations

• 4th Generation: High maneuverability, fly-by-wire systems, pulse-Doppler radar (e.g., MiG-29).

• 4.5 Generation: Advanced avionics, AESA radar, limited stealth features (e.g., Rafale).

• 5th Generation: Full stealth, sensor fusion, supercruise, network-centric warfare.

• Examples of 5th-generation fighters: F-22 Raptor, F-35 Lightning II, Sukhoi Su-57.

• India currently operates Rafale, Su-30MKI, MiG-29, and Tejas, but none are fifth-generation fighters.

• India is developing the Advanced Medium Combat Aircraft (AMCA).

• Stealth technology reduces radar detection.

• Sensor fusion combines data from multiple sensors into a single operational picture.