By freshers, do you mean freshman? 1st year student?
Honestly I do not know if any understanding of circuits is expected yet since 1st year is typically doing the basics, math science etc.
if you are older and in your EE courses I would expect basic theory, and the building blocks within your field of study, also expect you to have good grasp of op amp design and possibly basic digital logic.
When I interviewed college grad for ic jobs i would ask about the various single stage amps. about how to increase gain or bandwidth. about what the effects are of changing the body voltage of a device. and some simple k-maps
i also showed a logic gate i made out of pass fets and had them try to figure it out, off/on of gates should be easily determined by analog designer. and then would see where they were stronger and go more advanced in that direction
what interviewers hate is the regurgitation of memorized information without understanding the meaning. this is easily noticed when you make a small change that makes the statement no longer true, and watch the be unable to step back and relook at problem.
-Pb