Yes, you can use a separate sheet for rough work for each concept in Paper II. Here's why:

1. Organization and clarity:
Using a separate sheet for rough work for each concept can help you organize your thoughts and ideas clearly. It allows you to focus on one concept at a time, ensuring that your rough work is neat and easy to understand.

2. Avoiding confusion:
By using separate sheets, you can avoid confusion and prevent mixing up different concepts. This is particularly important in exams like UPSC where multiple concepts are tested within a single paper. Having separate sheets for each concept ensures that you can easily refer back to your rough work without any confusion.

3. Better time management:
Using separate sheets can also help you manage your time more effectively. When you have a dedicated sheet for each concept, you can quickly refer to your rough work without wasting time searching through a jumble of calculations and notes. This allows you to allocate your time more efficiently and maximize your productivity during the exam.

4. Easy revision:
Having separate sheets for each concept makes it easier to revise your rough work. When you review your answers later, you can focus on one concept at a time, making it easier to identify any mistakes or areas that need improvement. It also helps in keeping your revision organized and systematic.

5. Presenting a clean and professional answer sheet:
Using separate sheets for rough work allows you to present a clean and professional answer sheet. Since rough work is not graded, it is important to keep it separate from your final answers. By using separate sheets, you can ensure that your final answer sheet is neat, organized, and without any unnecessary scribbles or calculations.

Conclusion:
Using a separate sheet for rough work for each concept in Paper II is a beneficial practice. It helps in organizing your thoughts, avoiding confusion, managing time effectively, facilitating easy revision, and presenting a clean answer sheet. By following this approach, you can enhance your performance in the UPSC exam and increase your chances of success.