Two light signals are traveling through a piece of crown glass of length 30 km (it might be an optical fiber.) One of the signals uses red light, and the other uses blue light.
(a) If the signals travel straight through the glass with no reflections from the surfaces, which signal arrives first, the red one or the blue one?
(b) What is the time delay between the instants the faster and slower signals arrive? The data in Figure 24.20 will be useful.