Questions for Chapter 5

From the book

2. What is a spectrum and how do we see one?

3. Give an example from everyday life of each of the four major types of interaction between matter and light.

4. Define wavelength, frequency, and speed for a wave.

5. What do we mean when we say that light is an electromagnetic wave?

6. What is a photon? In what way is a photon like a particle? In what way is it like a wave?

7. List the different forms of light in order from lowest to highest energy. Would the list be different if you went in order from lowest to highest frequency? From shortest to longest wavelength? Explain.

8. Briefly describe the structure of an atom. How big is an atom? How big is the nucleus in comparison to the entire atom?

9. What determines an atom's atomic number? What determines its atomic number? Under what conditions are two atoms different isotopes of the same element? What is a molecule?

10. What is electrical charge? Will an electron and a proton attract or repel one another? Will two electrons attract or repel one another? Explain.

11. Describe the phase changes of water as you heat it starting from its solid phase, ice. What happens at very high temperatures? What is a plasma?

12. What do we mean when we say that energy levels are quantized in atoms? Under what circumstances can energy level transitions occur?
13. How do we convert a spectrum shown as a band of light (like a rainbow) into a graph of the spectrum?

14. Describe the conditions that would cause us to see each of the three basic types of spectra. What do we see in the Sun's spectrum shown on the opening page of this chapter?

15. How can we use emission or absorption lines to determine the chemical composition of a distant object?

16. Describe two ways in which the thermal radiation spectrum of an 8,000K star would differ from that of a 4,000 K star.

17. Describe each of the key features of the spectrum in Figure 5.21 and explain what it tells us about the object.

18. Describe the Doppler effect for light and what we can learn from it. What does it mean to say that radio waves are blue shifted? Why does the Doppler effect widen the spectral lines of rotating objects?

Test Your Understanding

Does It Make Sense? Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly. Not all of these have definitive answers, so your explanation is more important than your chosen answer.

1. The walls of my room are transparent to radio waves.

2/ Because of their higher frequencies, X rays must travel through space faster than radio waves.

3. If you could see infrared light, you would see a glow from the backs of your eyelids when you closed your eyes.

4. If you had X-ray vision, you could read this entire book without turning any pages.

5. Two isotopes of the element rubidium differ in their number of protons.

6. A “white hot" object is hotter than a “red hot" object.

7. If the Sun's surface became much hotter (while the Sun's size remained the same), the Sun would emit more ultraviolet light but less visible light than it currently emits.

8. If you could view a spectrum of light reflecting off a blue sweatshirt, you'd find the entire rainbow of color.

9. Galaxies that show redshifts must be red in color.

10. If a distant galaxy has a substantial redshift (as viewed from our galaxy), then anyone living in that galaxy would see a substantial redshift in a spectrum of the Milky Way Galaxy.

Other questions