Physics · Class 12 · Chapter 13
Nuclei
11 lessons 87 min 2 simulations
What is a nucleus made of, how big is it, and why does it hold together when its protons repel one another? This chapter builds the nucleus from protons and neutrons, measures it with R = R₀A^(1/3), and uses E = mc² to turn the mass defect into binding energy. The binding-energy-per-nucleon curve then explains where nuclear energy comes from: heavy nuclei release it by splitting (fission) and light nuclei by joining (fusion), which powers reactors and the stars.
What the exam asks
NEET asks for the atomic mass unit and 1 u = 931.5 MeV/c², the notation ᴬ_ZX with isotopes, isobars and isotones, R = R₀A^(1/3) with R₀ = 1.2 fm and the constant nuclear density (about 2.3 × 10¹⁷ kg m⁻³), mass defect and binding energy, the features of the Ebn–A curve (peak about 8.75 MeV at A = 56, 7.6 MeV at A = 238), the properties of the nuclear force, and the energy released in fission (about 200 MeV) and fusion. Marks are lost by forgetting the electrons' masses when using atomic masses, by mixing up binding energy with binding energy per nucleon, and by saying nuclear density grows with A.
Lessons
11 lessons · 87 min
1Atomic mass unit and isotopesNCERT §13.1, §13.27 min2Protons, neutrons and nuclidesNCERT §13.27 min3Size of the nucleusNCERT §13.310 min 1 sim4Mass–energy equivalenceNCERT §13.4.17 min5Mass defect and binding energyNCERT §13.4.27 min6Binding energy curveNCERT §13.4.210 min 1 sim7Nuclear forceNCERT §13.56 min8RadioactivityNCERT §13.67 min9Nuclear fissionNCERT §13.7, §13.7.17 min10Nuclear fusion in starsNCERT §13.7.2, §13.7.37 min11Chapter reviewMust-know facts, traps and formulas12 min