For an Internship at Tata steel
Asked about my favourite subject and I mentioned Fluids.
This is what it culminated into :
Iron Carbon diagram -- thoroughly.
Impulse and Reaction turbine and their velocity and pressure profiles.
P-T diagram of water.
Differential -- explanation.
Francis Turbine.
How is governor employed in a turbine?
Gear nomenclature...
Nothing much related to HR.
Indeed it was exhaustive.. 45 mins long..

Approach with a calm and cool mind and MOST importantly be Confident and Clear.
Even if u don't know the answer come up with some answer based on logic. What I think, they are looking after is the thought process.

Three students from mechanical engineering were selected on the basis of written test. After the interviews all three were selected.

Right after the completion of the internship they offered a PPO to two of us which both of us gladly accepted.