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# NCERT Solutions for Class 11 Physics Chapter 2- Units and Measurements

The chapter will deal with various physical units that are quantitatively used in physics. We will discuss the international system of units and their usage. We read about the measurements of a length over both short and long distances.

The chapter also teaches us about the measurement of masses and their range. The students also learn about time and its measurements. The chapter also entails the accuracy of these measurements and its various shortfalls. We also read about how significant numbers are measured and calculated. The chapter concludes by teaching about the dimensions of physical quantities and their formulae.

- Physics is based on the measurement of physical quantities.
- Certain physical quantities are considered to certain or fundamental physical quantities like length, mass, time etc.
- The chapter tells us about the CGS, the FPS, and the MKS systems respectively.
- The chapter also contains derivatives and formulae to measure the distance over long and short distances.
- We will learn to calculate length even at the molecular level.
- Next, we move on to the measurement of mass.
- We learn about the mass of different atomic and sub-atomic particles and the different ways to calculate them.
- The chapter also includes the measurement of time.
- We will learn about the different standards of time and the ways to calculate them.
- The chapter also illustrates the different methods of finding errors in our measurement calculations.
- These errors include – systematic errors, random errors, least count error, absolute, relative, and percentage errors.
- Derivatives are also required to determine these errors.
- The reliable digits in derivatives plus the uncertain first figures are known as significant numbers.
- We will learn about arithmetic operations with significant numbers and how to round them off.
- The chapter concludes by telling us about the dimensions of physical quantities and their application.
- For example, the acceleration of gravity on the moon is one-sixth of earth, but the law of gravity is followed in both.

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## Key Features of the NCERT Solutions for Class 11 Physics Chapter 2: Units and Measurements

- Illustrative solutions which provide a theoretical and practical understanding of the chapters.
- The answers provided have been written in an easy and comprehensible language aimed at increasing the understanding of children.