JEE Advanced Model Paper 15 with solutions for online practice

There is a detective submarine installed inside sea after 26/11 incident to detect terrorists. It is moving with constant speed v0 along a straight line and it sends a wave which travels with speed vω = 1100 m/s vm = 1100 m/sin water. Initially waves are getting reflected from a fixed island and the frequency detected by the submarine is found to be 20% more than the original frequency. When a terrorist ship moving towards the submarine with constant speed vs comes in between the submarine and the island, frequency of waves reflected from the ship is 80% more than the original frequency. (Density of sea water is 103 kg/m3.)