## Chapter Topics:

Energy of a photon
The photoelectric effect
Wave particle duality
Energy levels in atoms
X-ray spectra
The uncertainty principle

## Learning Objectives:

(a) Show an appreciation of the particulate nature of electromagnetic radiation.

(b) Recall and use the equation E = hf for the energy of a photon.

(c) Show an understanding that the photoelectric effect provides evidence for the particulate nature of electromagnetic radiation while phenomena such as interference and diffraction provide evidence for the wave nature.

(d) Recall the significance of threshold frequency.

(e) Recall and use the equation ½mvₘₐₓ² = eVₛ, where Vₛ is the stopping potential.

(f) Explain photoelectric phenomena in terms of photon energy and work function energy.

(g) Explain why the stopping potential is independent of intensity whereas the photoelectric current is proportional to intensity at constant frequency.

(h) Recall, use and explain the significance of the equation hf = Φ + ½mvₘₐₓ².

(i) Describe and interpret qualitatively the evidence provided by electron diffraction for the wave nature of particles.

(j) Recall and use the relation for the de Broglie wavelength λ = h/p.

(k) Show an understanding of the existence of discrete electronic energy levels in isolated atoms (e.g. atomic hydrogen) and deduce how this leads to the observation of spectral lines.

(l) Distinguish between emission and absorption line spectra.

(m) Recall and solve problems using the relation hf = E₂ - E₁.

(n) Explain the origins of the features of a typical X-ray spectrum.

(o) Show an understanding of and apply ΔpΔx ≳ h as a form of the Heisenberg position-momentum uncertainty principle to new situations or to solve related problems.