Chapter 30, Problem 65PP

Figure 30.25b shows how continuous refraction in the ionosphere enables long-distance radio communication. Waves launched at angles steeper than θ don't refract enough to return to Earth, so they propagate through the ionosphere and on to space. You can therefore conclude that

1. a. all points between A and B receive stronger signals from A than point B receives.
2. b. points between A and B can't receive signals from A via the ionosphere
3. c. the refractive index must become infinite at the maximum altitude of the radio signal.