Xét nguyên tử hiđrô theo mẫu nguyên tử Bo. Lấy r0 = 5,3.10^-11 m; me = 9,1.10

\(F = m{a_{ht}} \Rightarrow k.\frac{{{e^2}}}{{{r^2}}} = m.\frac{{{v^2}}}{r} \Rightarrow k.\frac{{{e^2}}}{{{n^2}{r_0}}} = m.{v^2} \Rightarrow {9.10^9}.\frac{{{{\left( {1,{{6.10}^{ - 19}}} \right)}^2}}}{{{3^2}.5,{{3.10}^{ - 11}}}} = 9,{1.10^{ - 31}}{v^2} \Rightarrow v \approx 728553m/s\)

\(s = vt = {728553.2.10^{ - 8}} \approx 0,0146m = 14,6mm\). Chọn B