I'm from Electronics and Instrumentation as my college (BITS Pilani) does not have a Electronics and Communication branch. Which paper am I eligible for, ECE or Instrumentation (IN) ?
you can apply in any one , they don't ask about the eligiblity regarding your subject. Even if you are from electronics background, you can give exam for mechanical or any other field.
instrumentation is preferable for you because there is less competition.
on the other hand you wouldn't have to study communication system chapter, which is a tough paper.