Atoms and Nuclei
The chapter Atoms and Nuclei forms an important part of modern physics in JEE Main.
It explains the structure of atoms, nuclear properties, radioactive decay, and energy released in nuclear reactions.
This chapter builds the foundation for understanding atomic models and nuclear phenomena.
Topics Covered
- Alpha Particle Scattering Experiment
- Rutherfordβs Nuclear Model of Atom
- Bohrβs Model of Hydrogen Atom
- Energy Levels and Spectral Series
- Excitation and Ionization Energy
- Composition of Nucleus
- Atomic Mass and Mass Defect
- Binding Energy and Stability of Nucleus
- Radioactivity
- Alpha, Beta and Gamma Decay
- Law of Radioactive Decay
- Half-Life and Mean Life
- Nuclear Fission and Fusion
Important Formulas
Bohr Radius:
rn = n2r1
Energy of nth Orbit:
En = -13.6 / n2 eV
Radioactive Decay Law:
N = N0e-Ξ»t
Half-Life:
T1/2 = 0.693 / Ξ»
Binding Energy:
B.E = Ξm Γ 931.5 MeV
JEE Main Preparation Tips
- Memorize all Bohr model equations.
- Practice numerical problems on half-life and decay constant.
- Understand binding energy graph and nuclear stability.
- Solve previous year JEE Main questions for better concept clarity.
Exam Weightage: Usually 1β2 questions are asked from this chapter in JEE Main.
