NCERT Solutions Class 12 Physics Chapter 13 - Nuclei

Chapter 14: Nuclei of Physics (Class 12) is about the centre of an atom which represents the core of the atom and contains the majority of the mass of the atom. The previous chapter examined the electrons and their orbits around the atom, while this chapter explores the forces that keep neutrons and protons together, like the force between them. New concepts introduced in this chapter are: Nuclear mass, binding energy, Nuclear stability and how stable is an isotope. In addition, this chapter will provide a deeper understanding of Radioactivity (the natural breakdown of unstable nuclei) and the amount of energy released during Nuclear Fusion and Nuclear Fission. The concepts studied in this chapter will provide a fundamental basis for all other subjects that relate to Medical Imaging, Nuclear Energy and the Evolution of Stars; making it a chapter that has a great potential for scoring well on the CBSE Board Exams, JEE and NEET.

NCERT Solutions for Class 12 Physics Chapter 14 Nuclei provides students with a clear pathway to understanding the Mass-Energy Equivalence Principle as well as the Kinetics of Radioactive Decay. This provides a pathway of logical progression from the basic properties of Nuclear Physics to the Advanced Nuclear Physics of Nuclear Reactors.

1.0Download NCERT Solutions Class 12 Physics Chapter 13 Nuclei: Free PDF

An essential part of learning about nuclear science includes understanding Mass Defect and Radioactive Decay Laws. These concepts are integral to problem-solving using NCERT Solutions. Each NCERT Solution has a complete breakdown of calculations, including the energy associated with binding an individual nucleon, the half-life of an element, and the average lifetime of an atom, therefore, there is great value in ensuring you understand these concepts related to the Strong Nuclear Force and Q-Values from Nuclear Reactions. All NCERT Solutions can be downloaded as PDF files for student use when preparing Energy Release Problems.

2.0Class 12 Physics Chapter 13 Nuclei: Key Concepts

This chapter focuses on the composition of the nucleus and the energy associated with nuclear transformations. The key lessons include:

• Atomic Masses and Composition of Nucleus: Understanding isotopes, isobars, and isotones, and the role of neutrons in nuclear stability.
• Size of the Nucleus: Learning the empirical formula for nuclear radius (R = R_0 A^{1/3}) and the exceptionally high density of nuclear matter.
• Mass-Energy Equivalence and Binding Energy: Applying Einstein’s E=mc^2 to calculate the mass defect and the binding energy that keeps the nucleus intact.
• Nuclear Force: Studying the properties of the strong nuclear force, which is short-ranged but powerful enough to overcome the electrostatic repulsion between protons.
• Radioactivity: Analyzing alpha, beta, and gamma decay, and the mathematical derivation of the exponential decay law.
• Nuclear Energy (Fission and Fusion): Exploring the split of heavy nuclei and the combination of light nuclei, including the principles of nuclear reactors.

3.0Key Features of NCERT Solutions for Class 12 Physics Chapter 13

• Binding Energy Curve Analysis: The solutions provide a detailed interpretation of the binding energy curve, explaining why energy is released during both fission and fusion.
• Step-by-Step Decay Kinetics: Complex problems involving half-life (T_{1/2}) and activity are broken down into simple logarithmic or exponential steps.
• Decay Process Clarity: Clear distinctions are made between \alpha, \beta, and \gamma decay, including the changes in atomic and mass numbers for each.
  [Image illustrating alpha, beta, and gamma decay processes from an unstable nucleus]
• Mass Defect Calculations: The solutions provide a standardized method for using atomic mass units (amu) to find the energy released in various nuclear reactions.
• Reactor Physics Logic: Detailed explanations are provided for the roles of moderators, control rods, and coolants in a controlled nuclear chain reaction.