Introduction:
The IIT JAM Physics paper follows a specific marking scheme where each question carries a predetermined number of marks. However, there are certain special cases where the marking scheme may differ for certain questions. These cases are outlined below:

1. Numerical Type Questions:
In recent years, the IIT JAM Physics paper has introduced Numerical Type Questions (NTQs) alongside the Multiple Choice Questions (MCQs). The marking scheme for NTQs is slightly different as they do not have any negative marking. These questions require students to calculate the numerical value of the answer and enter it in the computer-based test interface. The answer is evaluated by the computer, and if it falls within the acceptable range, the student is awarded full marks. However, if the answer is incorrect or falls outside the acceptable range, no marks are awarded.

2. Multiple Correct Answer Questions:
In some cases, certain questions in the IIT JAM Physics paper may have more than one correct answer. In such cases, the marking scheme is adjusted to account for the multiple correct options. Each correct option is assigned a certain weightage, and the total marks for the question are divided among these correct options. Incorrect options are awarded zero marks. The exact weightage for each correct option is mentioned in the question paper.

3. Matrix Match Type Questions:
Matrix Match Type Questions consist of two columns - Column I and Column II. Each item in Column I may have one or more matching items in Column II. Students are required to match the items from Column I to the correct items in Column II. The marking scheme for these questions is typically mentioned in the question paper. Each correct match is awarded a certain number of marks, while incorrect matches are penalized with negative marks.

4. Partial Marking:
In some cases, particularly in subjective or descriptive type questions, partial marking may be applied. This means that even if the answer is not completely correct, students can still receive some marks based on the steps or approach they have followed. The marking scheme for partial marking is usually specified in the question paper or exam instructions.

Conclusion:
While the general marking scheme for the IIT JAM Physics paper follows a specific pattern, there are certain special cases where the marking scheme may be different. These cases include Numerical Type Questions, Multiple Correct Answer Questions, Matrix Match Type Questions, and Partial Marking for subjective questions. It is important for students to familiarize themselves with these special cases and understand the specific marking scheme for each question type to maximize their scores in the exam.