📘 Q.3 IAS Prelims 2024 — Science & Technology (Radar Applications)
🧷 Authentic Classroom Explanation by IAS Monk
📌 The Question:
Consider the following activities:
- Identification of narcotics on passengers at airports or in aircraft
- Monitoring of precipitation
- Tracking the migration of animals
In how many of the above activities can radars be used?
(a) Only one
(b) Only two
(c) All three
(d) None
✅ Answer: (b) Only two
🧑🏫 Classroom Explanation:
Radar (Radio Detection and Ranging) works by transmitting radio waves and analysing the reflected signals (echoes) to detect, locate, and track objects.
🔹 Activity 1 – Identification of narcotics at airports ❌
- Narcotics detection primarily uses X-ray scanners, CT scanners, sniffer dogs, and chemical sensors.
- Radar waves are not suitable for identifying chemical substances like drugs.
➡️ Hence, not correct.
🔹 Activity 2 – Monitoring of precipitation ✅
- Weather radars (Doppler radars) are widely used to monitor:
- Rainfall intensity
- Storm systems
- Cyclones and cloud movement
➡️ Correct.
🔹 Activity 3 – Tracking migration of animals ✅
- Radar is extensively used in ecological and biological studies to track:
- Bird migration
- Bat movement
- Insect swarms
- Radars help determine altitude, speed, direction, and timing of migration.
➡️ Correct.
✔️ Therefore, two activities (2 and 3) use radar.
🔍 Curiosity Raiser:
🦅 Ever wondered how scientists track birds flying thousands of kilometres at night — without GPS tags?
👉 Radar sees what eyes cannot.
📚 Enrichment Notes (UPSC Edge):
- Doppler Weather Radar (DWR) is used by IMD for cyclone tracking
- Radar ornithology is a growing scientific field
- Radar cannot identify chemical composition, only objects and motion
- Millimetre-wave scanners used in airports are not classical radars
🧘 IAS Monk Whisper:
📡 Some tools do not search for substances — they search for movement.
Understanding the tool reveals its limits.