21. Is daytime a bit longer or a bit shorter because of atmospheric refraction? (29.9)

22. As light passes through glass or water, do the high or low frequencies of light interact more in the process of absorption and reemission, and therefore lag behind? (29.10)

23. Why does blue light refract at greater angles than red light in transparent materials? (29.10)

24. What conditions are necessary for viewing a rainbow in the sky? (29.11)

25. How is a raindrop similar to a prism? (29.11)

26. What is the critical angle in terms of refraction and total internal reflection? (29.12)

27. Why are optical fibers often called light pipes? (29.12)

Think and Explain
8. If you were spearing a fish with a spear, would you aim above, below, or directly at the observed fish to make a direct hit? Would your answer be the same if you used laser light to “spear” the fish? Defend your answer.

9. A rainbow viewed from an airplane may form a complete circle. Will the shadow of the airplane appear at the center of the circle? Explain with the help of Figure 29.26.

The rainbow is seen in a part of the sky opposite the sun and is
centered on the imaginary line extending from the sun to the observer.

10. The photo below shows two identical cola bottles, each with the same amount of cola. The right bottle is in air, and the left bottle encased in solid plastic that has nearly the same “index of refraction” as glass (the speed of light in the plastic and in glass are nearly the same). Which bottle shows an illusion of the amount of cola? How does the other bottle give a truer view of its contents?