ISI Entrance exam consists of two papers, namely Paper 1 and Paper 2:

Paper 1 consists of 30 Multiple choice questions whose answers have to be filled on an OMR sheet provided during the exam.

Paper 2 consists of 8 Subjective questions in which one has to write the complete solutions of the questions.

Also, Paper 2 is graded only is a student scores a particular minimum marks in Paper 1.

A student has to appear on both papers, 1 and 2. Being absent in any of the papers directly cancels the candidature of the student to get admission in ISI.