the atomic transition problem. Let E2- E = hw %3D | for two atomic states, u(@) be the radiation density, N be the number of atoms in state 1, and N2 that in state 2. B12 is the Enstein coffeicent for absorption, B1 that transition probability for emission, and A the spontaneous emission coefficient. Find N2/N

mh.8

3. a) Alpha particles of the same initial speed are shot at the same intensity toward gold, silver, and aluminum foils of the same thickness. They are observed at a detector at a fixed scattering angle, 0 0°. What would the ratios of the number of alpha particles scattered by the gold and silver foils to the aluminum foil, No Au 13). NaAl and respectively, be? (ZAu = 79, ZAg = 47, ZAI Na Ag NaAl b) Compare the number of a particles of fixed kinetic energy scattered through an angle of 10° (call this Na(10°)) with the number scattered through an angle of 20° (Na (20°)) for Rutherford scattering by a thin gold foil of fixed thickness. Compute Na (10⁰) Na (20°). p2 Rutherford's scattering model assumes that the alpha particles experience a Coulomb repulsion, F = KqZe from the nucleus of the foil's atom. If, in a head-on collision the alpha particle has enough energy to get inside a uniformly charged Kqa Zer nucleus of radius R, the force law would change to F = R³ " point-nucleus…

Constants Ideal gas constant: = 8.314 J K mol- = 0.083 dm bar K mol = 0.082 dm atm K mol Avogadro's constant: NA = 6.022x1023 mol-! Boltzmann constant: k 1.38x1023 J K Speed of light: c = 3 x 10% m s Planck's constant: h = 6.626x1034 J s 1 bar = 105 Pa 1 atm = 101325 Pa Relations U = NKT²(n = + k In Q S = %3D A = -kT In Q G = -NkT In) R.