Consider the following activities : 1. Identification of narcotics on passengers at airports or in aircraft 2. Monitoring of precipitation 3. Tracking the migration of animals In how many of the above activities can the radars be used ?
- (a) Only one
- (b) Only two ✓ UPSC's answer
- (c) All three
- (d) None
Why the answer is (b)
• Radar detects objects by bouncing radio waves off them; its uses depend on what reflects the waves.
• Activity 2 qualifies: weather (Doppler) radars track precipitation, its intensity and movement — the IMD's network is built on them.
• Activity 3 qualifies: weather and dedicated radars track flocks of migrating birds, bats and insects; 'aeroecology' uses radar data to map migration.
• Activity 1 does not qualify: narcotics on passengers are detected by X-ray, millimetre-wave body scanners, ion-mobility spectrometers and sniffer dogs, not by radar.
• Hence two of the three, option (b).
Why the other options are wrong
- (a) Only one
- Both precipitation and animal migration are tracked by radar, so the count is two.
- (c) All three
- Radar cannot identify narcotics on passengers.
- (d) None
- Weather radar and migration tracking are genuine radar uses.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2024, held on 16 June 2024. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.