IAS 1997 — Science Physics

Which of the following statements with regard to stealth technology is/are correct? 1. Stealth objects have a very small radar cross-section and are coated with Radar Absorbing Material. 2. Stealth objects can be detected using specific frequencies. 3. Stealth objects are coated with metamaterials to increase the scattering of electromagnetic radiation. Select the answer using the code given below:

Consider the following statements : 1. Statement-I : Giant stars live much longer than dwarf stars. 2. Statement-II : Compared to dwarf stars, giant stars have a greater rate of nuclear reactions. Which one of the following is correct in respect of the above statements ?

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 ?

Consider the following pairs: Objects in space | Description 1. Cepheids | Giant clouds of dust and gas in space 2. Nebulae | Stars which brighten and dim periodically 3. Pulsars | Neutron stars that are formed when massive stars run out of fuel and collapse How many of the above pairs are correctly matched?

Consider the following statements : 1. In a seismograph, P waves are recorded earlier than S waves. 2. In P waves, the individual particles vibrate to and fro in the direction of wave propagation whereas in S waves, the particles vibrate up and down at right angles to the direction of wave propagation. Which of the statements given above is/are correct?