2. The He-Ne laser emits red light with a wavelength of 1 = 633 nm. a. What is the frequency of that light? b. Given that the time for light to travel a distance L parallel to Earth's motion through a hypothetical ether is L L 2L t= C ctu C 1 while its time to travel perpendicular to Earth's motion is 2L tl = use the binomial expansion to find an approximate formula for f - t1. c. Find the value of t - ti for Earth's motion of v = 30km/s if L = 1m. Express your answer as a fraction of the period of the 633 nm red light. d. What did Michelson and Morley observe when they tried to measure the phase difference between the two arms, and why was their result important