2 Answer any two questions in this section.

Each question is worth 5 marks.

1. Compare and contrast fluorescence and phosphorescence.
2. A photon of wavelength 250nm is absorbed by a molecule with an approximate mass of (800g/mol). By how much does the velocity of the molecule change in the initial direction of travel of the photon?
3. Comment on the relationship between the contributions of Einstein and de Broglie to the development of quantum mechanics.