Practice question

**Nuclear size** order 10⁻¹⁵ m femtometer, atomic size 10⁻¹⁰ m, ratio 10⁵, nucleus contains protons and neutrons bound by strong force, density independent of A indicates incompressibility, R₀ determined from electron scattering experiments. The radius of a nucleus is given by R = R₀ A¹/³ , where A = 4 . A¹/³ = 4¹/³ ≈ 1.59 . R = 1.2 × 10⁻¹⁵ × 1.59 ≈ 1.9 × 10⁻¹⁵ m . 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 1.9 × 10⁻¹⁵ m, consistent with