Previous Year 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?
Only one
Only two
All three
None of these
Correct Answer: B
Detailed Solution
Radar is not used in Activity 1. The function of airport surveillance radar is to determine an aircraft’s position, distance, direction and speed. It does not chemically identify narcotics carried by a passenger.
X-ray scanners, computed tomography scanners, ion-mobility spectrometry, trace-detection systems, chemical sensors and trained sniffer dogs may be used to identify narcotics on passengers or in baggage. A millimetre-wave body scanner can reveal an object concealed on the body, but it does not itself chemically identify that object as a narcotic.
Radar is used in Activity 2. Weather radar transmits microwave pulses and analyses signals reflected by raindrops, snow and hail. The intensity or reflectivity of the returned signal is used to estimate the location and intensity of precipitation.
Doppler weather radar measures the radial velocity of precipitation particles to provide information about the speed and direction of winds within a storm. Dual-polarization radar assists in distinguishing more accurately between rain, snow and hail.
Radar is also used in Activity 3. Weather radars and specialized biological radars can track the migration of birds, bats and large insects. Radar can determine the timing, direction, altitude, speed and relative density of migration.
This field is known as radar ornithology or radar aeroecology. It assists in assessing bird-strike risks for aviation safety and studying wildlife migration patterns. Therefore, radar can be used in two of the three activities.