#nuclear fission

Nuclear Reactions - Fission, Fusion and Energy Release

Which process involves the splitting of a heavy nucleus into two intermediate mass fragments?

**Nuclear fission** splitting heavy nucleus like U-235 into intermediate mass fragments Ba and Kr plus neutrons, releases ~200 MeV per fission because product BE/A higher, mass defect converted to energy, controlled in reactors, uncontrolled in bombs. Fusion combining light nuclei D+T→He+n releases ~17.6 MeV, requires high temperature to overcome Coulomb barrier to bring nuclei close for strong force to act. Nuclear fission is the process where a heavy nucleus splits into two intermediate mass fragments, releasing energy due to the higher binding energy per nucleon in the resulting nuclei. Usi

Ref: NCERT > Physics Book > Atoms and Nuclei > Nuclear Reactions - Fission, Fusion and Energy Release

View Details

Nuclear Reactions - Fission, Fusion and Energy Release

What is the primary outcome of nuclear fission in terms of energy?

**Energy release in nuclear processes** always because final BE/A higher than initial, mass defect difference appears as kinetic energy of fragments and radiation, 1 u =931.5 MeV, high temperature in fusion provides kinetic energy to overcome Coulomb barrier, confinement needed, Sun's core temperature ~1.5×10⁷ K enables fusion. Nuclear fission converts mass defect into energy, initially as kinetic energy of fragments and neutrons, which is eventually transferred as heat, due to the increase in binding energy per nucleon. Using E_n = -13.6/n² eV, r_n = n² a₀, L = n h/2π, R = R₀ A^¹/³, BE = Δm c

Ref: NCERT > Physics Book > Atoms and Nuclei > Nuclear Reactions - Fission, Fusion and Energy Release

View Details

Mass Defect, Binding Energy and Binding Energy per Nucleon

Which process is responsible for the energy release in an atomic bomb?

**Energy equivalent** E= m c², 0.005 kg matter E=0.005×9×10¹⁶=4.5×10¹⁴ J, 0.01 kg 9×10¹⁴ J, mass defect 0.1 u => BE=0.1×931.5=93.15 MeV, mass defect from BE 149.04 MeV => Δm=149.04/931.5=0.16 u, BE per nucleon 8.5 MeV A=20 total BE=170 MeV. The energy in an atomic bomb comes from uncontrolled nuclear fission, where a heavy nucleus splits into lighter fragments, releasing energy due to increased binding energy per nucleon. Using E_n = -13.6/n² eV, r_n = n² a₀, L = n h/2π, R = R₀ A^¹/³, BE = Δm c² and 1 u = 931.5 MeV, evaluation yields Nuclear fission, consistent with Bohr model and nuclear bind

Ref: NCERT > Physics Book > Atoms and Nuclei > Mass Defect, Binding Energy and Binding Energy per Nucleon

View Details

Mass Defect, Binding Energy and Binding Energy per Nucleon

What is the main source of energy in nuclear reactors?

**Binding energy calculation** from mass defect, for nucleus mass number 28 BE 224 MeV BE/A=8 MeV, A=18 BE 144 MeV BE/A=8 MeV, BE/A indicates stability, fusion of light nuclei and fission of heavy release energy because product has higher BE/A, difference released. Nuclear reactors produce energy through nuclear fission, where heavy nuclei split into lighter fragments, releasing energy due to the increase in binding energy per nucleon. Using E_n = -13.6/n² eV, r_n = n² a₀, L = n h/2π, R = R₀ A^¹/³, BE = Δm c² and 1 u = 931.5 MeV, evaluation yields Nuclear fission, consistent with Bohr model an

Ref: NCERT > Physics Book > Atoms and Nuclei > Mass Defect, Binding Energy and Binding Energy per Nucleon

View Details

Mass Defect, Binding Energy and Binding Energy per Nucleon

What happens to the binding energy per nucleon when a heavy nucleus undergoes fission?

**Binding energy calculation** from mass defect, for nucleus mass number 28 BE 224 MeV BE/A=8 MeV, A=18 BE 144 MeV BE/A=8 MeV, BE/A indicates stability, fusion of light nuclei and fission of heavy release energy because product has higher BE/A, difference released. For heavy nuclei (A > 170), the binding energy per nucleon is lower (~7.6 MeV). Fission into intermediate mass fragments (A ≈ 120) increases it to ~8.5 MeV, releasing energy. Using E_n = -13.6/n² eV, r_n = n² a₀, L = n h/2π, R = R₀ A^¹/³, BE = Δm c² and 1 u = 931.5 MeV, evaluation yields Increases, consistent with Bohr

Ref: NCERT > Physics Book > Atoms and Nuclei > Mass Defect, Binding Energy and Binding Energy per Nucleon

View Details

Mass Defect, Binding Energy and Binding Energy per Nucleon

Why does nuclear fission release more energy than chemical reactions?

**Mass defect** Δm = Z m_p + N m_n - M_nucleus, binding energy BE = Δm c², 1 u =931.5 MeV/c², BE per nucleon = BE/A, measures stability, peak ~8.8 MeV at Fe-56, for A=36 BE=288 MeV BE/A=8 MeV, for A=12 BE=96 MeV BE/A=8 MeV, for A=16 BE=127.5 MeV BE/A≈7.97 MeV, higher BE/A more stable. Nuclear fission involves changes in nuclear binding energy (order of MeV), which is about a million times larger than the energy from chemical bond changes (order of eV). Using E_n = -13.6/n² eV, r_n = n² a₀, L = n h/2π, R = R₀ A^¹/³, BE = Δm c² and

Ref: NCERT > Physics Book > Atoms and Nuclei > Mass Defect, Binding Energy and Binding Energy per Nucleon

View Details