One problem with using optical fibers for communication is that a light ray passing directly down the center of the fiber takes less time to travel from one end to the other than a ray taking a longer, zig-zag path. Thus light rays starting at the same time but traveling in slightly different directions reach the end of the fiber at different times. This problem can be solved by making the refractive index of the glass change gradually from a higher value in the center to a lower value near the edges of the fiber. Explain how this reduces the difference in travel times.
PHYS 1010 Notes Week 12 April 48 General theory of relativity Covers accelerating and nonaccelerating reference frames You can always tell if you are accelerating by dropping an object and watching it move, but we can't distinguish between an accelerating reference frame and gravity Airplanes travel in curved paths because they take the shortest route...
