IIT JEE Mains and Advanced PYQ: Rotation

Two coaxial discs, having moments of inertia 𝑰1 and 𝑰1/2 are rotating with respective angular velocities 𝝎1 and 𝝎1/2, about their common axis. They are brought in contact with each other and after some time they rotate with a common angular velocity. If 𝑬f and 𝑬i are the final and initial total energies, then (𝑬f - 𝑬i) is?
(2019 Main)
IIT JEE Mains and Advanced PYQ: Rotation #neet #jeemain #jeeadvance #physics#pyqseries

[@KoustavMukherjee-d1o]

ans (c)

[@KoustavMukherjee-d1o]

wrong concept

[@KoustavMukherjee-d1o]

wrong concept

[@AaravGupta-jp5mh]

Can you please elaborate us on the CORRECT concept!!!

[@Riyaansh-yv5ix]

based on which book???