Yes, you can definitely attempt mock tests for UPSC Law Optional subject during your study breaks. Here's why:

1. Enhances Time Management Skills:
- Mock tests provide a simulated exam environment, helping you practice time management skills.
- By attempting these tests during study breaks, you can train yourself to answer questions within the allocated time frame.

2. Improves Question-solving Speed:
- Regularly attempting mock tests can help you increase your question-solving speed.
- During study breaks, you can work on questions that require quick thinking and problem-solving abilities, which are essential for the UPSC exam.

3. Identifies Weak Areas:
- Mock tests allow you to assess your strengths and weaknesses in different topics.
- Analyzing your performance in these tests during study breaks can help you identify areas that require more attention and revision.

4. Builds Exam Confidence:
- Mock tests provide a platform to experience the exam-like environment and reduce exam anxiety.
- By attempting these tests during study breaks, you can boost your confidence and reduce stress.

5. Evaluates Preparation Level:
- Mock tests help you gauge your preparation level and track your progress.
- Answering these tests during study breaks allows you to assess your understanding of the subject matter and identify any gaps in your knowledge.

6. Familiarizes with Exam Pattern:
- UPSC mock tests are designed to reflect the actual exam pattern and difficulty level.
- Attempting these tests during study breaks familiarizes you with the format, types of questions, and marking scheme of the UPSC exam.

7. Reinforces Concepts:
- Mock tests provide an opportunity to reinforce the concepts you have studied.
- During study breaks, attempting these tests helps consolidate your knowledge and reinforce the topics you have covered.

8. Provides Feedback and Analysis:
- Mock tests offer detailed feedback and analysis of your performance.
- Utilizing your study breaks to review the feedback and analysis can help you understand your strengths and weaknesses better.

Conclusion:
Taking mock tests during your study breaks for the UPSC Law Optional subject can be highly beneficial. It enhances time management skills, improves question-solving speed, identifies weak areas, builds exam confidence, evaluates preparation level, familiarizes with the exam pattern, reinforces concepts, and provides valuable feedback and analysis. By incorporating mock tests into your study routine, you can enhance your overall preparation and increase your chances of success in the UPSC exam.