Wave/particle duality

Q4. The diagram shows some of the electron energy levels of an atom.

An incident electron of kinetic energy 4.1 × 10–18 J and speed 3.0 × 106 m s–1 collides with the atom represented in the diagram and excites an electron in the atom from level B to level D.

(a) For the incident electron, calculate

(i) the kinetic energy in eV,

(ii) the de Broglie wavelength.

(4 marks)

(b) When the excited electron returns directly from level D to level B it emits a photon. Calculate the wavelength of this photon.

(3 marks)

(Total 7 marks)