UPSC Prelims 2024 · GS Paper I
Question 34: Science and Technology
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 ?
AnswerUPSC’s answer is (b).
Radars send out radio waves and read the echoes. Weather radar, including Doppler radar, tracks rain, snow and storms, so it can monitor precipitation. Radars are also used to track birds, bats and insect swarms in migration. Radar cannot identify narcotics on passengers; that needs sniffer dogs and chemical trace detectors. So two of the three activities use radar.
- 1. Radar cannot detect narcotics on people; sniffer dogs and trace detectors do that.
- 2. Weather radar monitors rain and other precipitation.
- 3. Radar tracks the movement of migrating birds and other flying animals.
How you could have got this
No shortcut here: in a “how many” question, ruling out options doesn’t help. Every statement has to be judged.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong: two activities, precipitation monitoring and tracking migration, use radar.
- (b) Right: radar is used for precipitation and animal migration, not for finding narcotics.
- (c) Wrong: radar cannot identify narcotics on passengers.
- (d) Wrong: radar is used for precipitation and animal migration.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2024, General Studies Paper I, Series A. The paper on upsc.gov.in.