6. Unobtainium (6 points) A transparent bar of unobtainium (a rare and fictitious material) is submerged in a tank of water. A red laser beam traveling through the water hits the side of the unobtainium at an angle of 0, = 21, as shown in the figure below. The index of refraction of water is n, = 1.33. The refracted ray then has an angle of 0,, = 27 in the unobtainium. (a) (2 points) What is the index of refraction of unobtainium? (b) (2 points) At what speed does the laser beam travel through the unobtainium? Is this faster or slower than the speed of the laser through the water? Explain why. (c) (2 points) When the laser beam hits the bottom edge of the rectangle, will some of the beam pass through back in to the water, or will there be total internal reflection? Explain your answer. Water Unobtainium