1. What does it mean when we say that the energy of something is "quantized"?

3. How might you explain the concept of quantization to a younger child (brother, sister, niece, etc.), using money as the quantized entity?

5. What assumption allowed Planck to account for the observed features of blackbody radiation?

7. Describe the photoelectric effect. Name some devices that make use of this process.

9. Sodium undergoes the photoelectric effect, with one electron absorbing a photon of violet light and another absorbing a photon of ultraviolet light. What is different about the two electrons afterward?

11. What aspects of the photoelectric effect can be explained without recourse to the concept of the photon? What aspects of this phenomenon require the existence of photons for their explanation?

13. If sunlight can be conceived of as a beam of photons, each of which carries a certain amount of energy and momentum, why don't we experience (or feel) any recoil as these particles collide with our bodies when, say, we're at the beach on a sunny day?

15. A mixture of hydrogen and neon is heated until it is luminous. Describe what is seen when this light passes through a prism and is projected onto a screen.

17. Discuss what is meant by the term ionization. Give two ways by which an atom might acquire enough energy to become ionized.