# NCERT Solutions for Class 12 Physics Chapter 13 Nuclei

NCERT solutions for class 12 Physics chapter 13 Nuclei: Do you know that the size of an atom is 10000 times the size of a nucleus? But the nucleus contains 99.9% of the mass of an atom. We know that an atom has a structure. Does the nucleus also have a structure? If so what are the constituents and how they are arranged? All these questions are answered in NCERT solutions for class 12 Physics chapter 13 Nuclei. This chapter comes under modern Physics and you can expect at least one questions for CBSE board exam from NCERT solutions for class 12 Physics chapter 13 Nuclei.

Important formulas:

• Radii of the nuclei, $R=R_0A^{\frac{1}{3}}$

Where A is the mass number and $R_0=1.2fm$

• Mass defect: $\Delta M=(Zm_p+(A-Z)m_n)-M$

Here Z is the atomic number, M is the mass of the nucleus and A is the mass number.    This equation tells that the mass of the nucleus is always less than the mass of their constituents.

• Another important relation of NCERT solutions for class 12 Physics chapter 13 Nuclei is Einstein's mass-energy relation.

$E_b=\Delta Mc^2$

Where c is the speed of light.

• Another main concept of NCERT grade 12 chapter 13 Nuclei is the law of radioactive decay. This is given by $N=N_0e^{-\lambda t}$

Where N is the number of nuclei at any time t, $N_0$ is the number of nuclei at any time $t_0$ and lambda is disintegration constant.

• The half-life of a radionuclide is given by $T_{\frac{1}{2}}=\frac{ln2}{\lambda}$

Where lambda is the disintegration constant.

## The Topics of  NCERT solutions for class 12 Physics chapter 13 Nuclei are listed below

13.1 Introduction

13.2 Atomic Masses And Composition Of Nucleus

13.3 Size Of The Nucleus

13.4 Mass-energy And Nuclear Binding Energy

13.4.1 Mass – Energy

13.4.2 Nuclear Binding Energy

13.5 Nuclear Force

13.6.2 Alpha Decay

13.6.3 Beta Decay

13.6.4 Gamma Decay

13.7 Nuclear Energy

13.7.1 Fission

13.7.2 Nuclear Reactor

13.7.3 Nuclear Fusion – Energy Generation In Stars

13.7.4 Controlled Thermonuclear Fusion

All the above-mentioned topics are important. After completing all these topics try to do NCERT class 12 chapter 13 exercises. If you are unable to solve or have any doubts we are providing you NCERT solutions for class 12 Physics chapter 13 Nuclei below:

View all solved questions of class 12 Physics, chapter 13 Nuclei here.

## NCERT Solutions for Class 12 Physics- Chapter wise

 Chapter 1 Electric Charges and Fields Chapter 2 Electrostatic Potential and Capacitance Chapter 3 Current Electricity Chapter 4 Moving charges and magnetism Chapter 5 Magnetism and Matter Chapter 6 Electromagnetic Induction Chapter 7 Alternating Current Chapter 8 Electromagnetic Waves Chapter 9 Ray Optics and Optical Instruments Chapter 10 Wave Optics Chapter 11 Dual nature of radiation and matter Chapter 12 Atoms Chapter 13 Nuclei Chapter 14 Semiconductor Electronics: Materials, Devices and Simple Circuits