Everything you need for this topic on one page: the ideas, the formulas, the traps, and free lectures that explain it well.
Last updated: 26 October 2026
Rutherford and Bohr models, hydrogen spectrum, nuclear size, mass defect, binding energy, radioactivity, fission and fusion.
Printable Atoms and Nuclei formula sheet: formulas, key ideas and traps on one page. Save it as a PDF for offline revision.
Appears in almost every JEE Main shift. Two or more Modern Physics questions per shift are common. Quick marks if formulas are fresh.
Prerequisites: Dual Nature of Matter and Radiation.
Chapter names follow the current rationalised NCERT textbooks. Read these sections before solving PYQs.
| Class | Book | Chapter | Sections JEE asks from |
|---|---|---|---|
| Class 12 | Physics Part II | Atoms | Bohr model of the hydrogen atom; The line spectra of the hydrogen atom; Energy levels; Atomic spectra |
| Class 12 | Physics Part II | Nuclei | Nuclear binding energy; Radioactivity; Nuclear energy; Mass-energy equivalence |
Question. A ²³⁸U nucleus (Z=92) undergoes alpha decay, emitting an alpha particle with kinetic energy 4.2 MeV. (a) Find the recoil kinetic energy of the daughter nucleus. (b) The alpha particle later captures one electron to form a He⁺ ion. Calculate the wavelength of the photon emitted when this electron transitions from n=2 to n=1. (Given: mass of alpha particle = 4 u, mass of daughter nucleus = 234 u, R = 1.097 × 10⁷ m⁻¹, hc = 1240 eV·nm)
Answer: (a) 72 keV (b) 30.4 nm
This example was solved twice independently and both solutions agree.
Full-chapter free lectures picked from YouTube search results by views, from established JEE channels (mostly in Hinglish). Use the subtopic list to jump straight to the part you need (timestamps come from each video's own chapter list). Watch one, then solve PYQs the same day.
Appears in almost every JEE Main shift. It is part of the official 'Atoms and Nuclei' unit in the JEE Main 2027 syllabus.
Eₙ = −13.6 Z²/n² eV; rₙ = 0.529 n²/Z Å; 1/λ = RZ²(1/n₁² − 1/n₂²); N = N₀e^(−λt), T½ = 0.693/λ.
Understand the key ideas from NCERT or one full lecture, learn the formula sheet, then solve 25–30 past JEE questions on the topic. Two or more Modern Physics questions per shift are common. Quick marks if formulas are fresh.
