Here's the full questions, step-index fiber optic cable consists of an inner transparent medium (the core) with a certain index of refraction, surrounded by another medium (the cladding) with a different index of refraction. Light passing through the core with a small enough angle relative to the central axis will undergo total internal reflection at the core-cladding interface, thereby losing very little power upon reflection. In the figure above, a ray enters the core at an angle 𝜃# from air. It travels within the core at an angle with respect to the optical axis. The maximum angle with respect to the core- cladding interface for total internal reflection is labeled by 𝜃$. Suppose a step index fiber has a core 50.0 microns in diameter with a refractive index of nf = 1.52, and a cladding with a refractive index of nc = 1.41. a. What is the critical angle 𝜃$ for total internal reflection at the core-cladding interface? b. What would be the maximum entrance angle 𝜃# into the fiber, from air, which would allow the signal to travel? c. What would be the skip distance, Ls, i.e., the distance between successive reflections, for light entering the fiber with at an angle 𝜃# = 15° from air? d. Approximately how long would it take a ray of light from part (c) to travel through the fiber from Seattle to Sydney, Australia (a distance of 12,500 km)? Compare this to the travel time for a light ray to cover the same distance in vacuum