Ten questions. The result tells you which lessons you may skip.
In the gold foil experiment, a very few alpha particles came almost straight back. This showed that
An alpha particle of \(5.76\,\text{MeV}\) is aimed head-on at a nucleus with \(Z = 80\). Take \(ke^2 = 1.44\,\text{MeV fm}\). The distance of closest approach is
By classical physics, an electron circling a nucleus
In Bohr's model the angular momentum of the electron on the orbit \(n = 2\) is
The radius of the orbit \(n = 3\) of \(\text{Li}^{2+}\) (\(Z = 3\)), with \(r_1 = 0.529\,\text{Å}\) for hydrogen, is
The electron of hydrogen on the orbit \(n = 2\) has kinetic energy
The ionisation energy of \(\text{He}^+\) (\(Z = 2\)) is
The shortest wavelength of the Balmer series of hydrogen, with \(1/R = 91.2\,\text{nm}\), is
Hydrogen atoms are excited to \(n = 4\). The number of different lines they can give out is
A hydrogen atom moving with kinetic energy \(K\) strikes a hydrogen atom at rest head-on. The least \(K\) that can excite the struck atom to \(n = 2\) is