Introduction
Today’s Physics live class for the NDA/CDS 2 2026 examination was dedicated to the fundamental topic Units and Dimensions, which serves as the foundation for almost every chapter in Physics. The objective of the session was to develop a strong conceptual understanding of physical quantities, systems of units, dimensional analysis, and their practical applications in solving examination-oriented questions. Since questions from this topic are frequently asked in NDA and CDS examinations, special emphasis was placed on both conceptual clarity and problem-solving techniques.
The session began with an introduction to physical quantities and their classification into fundamental and derived quantities. Students were guided through the SI system of units, along with the significance of base units and standardization in scientific measurements. Detailed explanations were provided on dimensions, dimensional formulae, and the distinction between units and dimensions to eliminate common misconceptions.
The strategy throughout the class was to build concepts progressively. After establishing the theoretical foundation, students learned systematic methods to derive dimensional formulae for various physical quantities. Particular attention was given to the applications of dimensional analysis, including checking the correctness of physical equations, deriving relationships between physical quantities, converting units from one system to another, and identifying dimensionless quantities. Numerous examples were discussed to demonstrate how these concepts are tested in competitive examinations.
To make the session exam-oriented, previous years’ NDA and CDS questions, along with carefully selected practice problems, were solved using short tricks and logical approaches. Students were encouraged to identify patterns in questions and apply dimensional reasoning instead of relying solely on memorization. Common mistakes made by aspirants were also highlighted, enabling students to avoid errors during the examination.
Conclusion
The class concluded with a comprehensive revision of all key concepts and important formulas related to Units and Dimensions. Students were advised to practice dimensional analysis regularly, as it strengthens analytical thinking and improves accuracy in solving Physics problems. By mastering this foundational topic, aspirants will be better prepared to tackle questions from subsequent chapters with greater confidence and efficiency, thereby enhancing their overall performance in the NDA/CDS 2 2026 examination.
