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 volume of a nucleus is proportional to A (since R ∝ A¹/³ and V ∝ R³ ), and the mass is also proportional to A , making the density (mass/volume) independent of A . 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 Volume proportional to mass number, consistent with Bohr