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#Coulomb scattering

2 public questions tagged with this topic.

Atomic Models - Rutherford, Thomson and Bohr

In an alpha-particle scattering experiment, a 5.5 MeV alpha-particle approaches a gold nucleus (Z = 79). What is the app

**Rutherford's nuclear model** atom has small massive positively charged nucleus with electrons orbiting, size ratio atomic to nuclear ~10⁵, nucleus ~10⁻¹⁵ m atom ~10⁻¹⁰ m, most alpha particles with large impact parameter pass undeflected, small fraction >90° scatter from close approach, centripetal force provided by Coulomb attraction k Z e²/r², fails to explain stability because accelerating charge should radiate and collapse. Energy conservation: K = (2Ze²/4πepsilon₀ d) . d = (2Ze²/4πepsilon₀ K) . K = 5.5 MeV = 5.5 × 1.6 × 10⁻¹³ = 8.8 × 10⁻¹³ J . d = (2 × 79 × (1.6 × 10⁻¹⁹)² × 9 × 10⁹/8.8 ×

Ref: NCERT > Physics Book > Atoms and Nuclei > Atomic Models - Rutherford, Thomson and Bohr

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Hydrogen Atom Properties - Radius, Speed and Energy

An alpha-particle with 4.0 MeV kinetic energy approaches a gold nucleus (Z = 79). What is the distance of closest approa

**Angular momentum** L_n = n h/2π, h=6.6×10⁻³⁴ J·s, L₂=2×6.6×10⁻³⁴/2π=2.11×10⁻³⁴ J·s, speed v_n = e²/(2 ε₀ h) ×1/n ≈2.2×10⁶/n m/s, kinetic energy ½ m v² =13.6/n² eV, illustrating Bohr model predictions for hydrogen-like atoms. d = (2Ze²/4πepsilon₀ K) . K = 4.0 × 1.6 × 10⁻¹³ = 6.4 × 10⁻¹³ J . d = (2 × 79 × (1.6 × 10⁻¹⁹)² × 9 × 10⁹/6.4 × 10⁻¹³) . d = (3.641 × 10⁻²⁸/6.4 × 10⁻¹³) ≈ 5.69 × 10⁻¹⁴ m ≈ 57 fm . 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 > Hydrogen Atom Properties - Radius, Speed and Energy

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