See if you can answer the following conceptual questions before moving on. You will need to be able to use the calculations covered in problem solving as well as explain the quantum theory and photoelectric effect.
Describe the concept of the quantization of energy. Include how it came about and how the ultraviolet catatrophe led to its development.
Explain the photoelectric effect.
| Your Responses | Sample Answers |
|---|---|
| Scientists used classical physics to predict what would happen in a blackbody radiation experiment. Unfortunately, the experiment failed to match the expected results. Max Planck came up with an explanation that energy in light waves was quantized and only if there was enough energy in the incident rays would light be emitted. He came up with the idea that the energy of a photon equals some quantized constant times the frequency of the incident light. E = hf. This went against the classical view that light was a continuous wave, rather it was a series of particles, called photons. | |
| If you shine light on a photoelectric metal, electrons will be emitted from the surface. The kinetic energy of the electron that is emitted depends on the energy of the incident wave (which is proportional to its frequency), and the work function of the surface. It is represented by the equation KE = hf - Φ. | |
