Introduction:
Preparing for the UPSC Physics Optional exam requires a systematic and efficient approach. One important aspect of preparation is selecting the right study materials and sources. In this context, the question arises whether it is better to revise from multiple sources or stick to one. Let us explore the advantages and disadvantages of both approaches.

Revising from Multiple Sources:
- Broad coverage: Revising from multiple sources can provide a broader coverage of the syllabus. Different sources may have their own unique perspectives, explanations, and examples, which can help in gaining a comprehensive understanding of the subject.
- Diverse perspectives: Multiple sources can offer diverse perspectives on various topics, allowing the aspirant to develop a well-rounded understanding of different concepts and theories.
- Cross-referencing: By revising from multiple sources, it becomes easier to cross-reference information and verify its accuracy. This helps in reinforcing the knowledge and identifying any discrepancies or gaps in understanding.
- Exam preparation: UPSC exams often have unpredictable question patterns. Revising from multiple sources can expose the aspirant to a wide range of questions and help in developing a flexible and adaptable approach towards answering them.

Sticking to One Source:
- Depth of understanding: Focusing on one source allows the aspirant to delve deeper into the concepts and theories. It enables a thorough understanding of the material, which can be beneficial, especially for complex topics.
- Time efficiency: Sticking to one source can save time and prevent information overload. Instead of spending excessive time comparing and contrasting different sources, the aspirant can concentrate on revising and consolidating the knowledge from a single reliable source.
- Consistency: Following a single source ensures consistency in the approach towards studying. It helps in maintaining a structured study plan and avoids the confusion that may arise from switching between multiple sources.

Conclusion:
Both revising from multiple sources and sticking to one source have their own advantages and disadvantages. The choice ultimately depends on the individual's learning style, time constraints, and personal preferences. It may be beneficial to initially revise from multiple sources to gain a broad understanding and then focus on a single source for in-depth revision. Regardless of the approach chosen, consistent practice, self-assessment, and regular revision are key to success in the UPSC Physics Optional exam.