A laser pointer is shined through air (n = 1.00) and enters another medium at an angle of 45 degrees. If the angle of refraction is 24 degrees, what is the index of refraction of the medium?

 Red light with a wavelength of 6.45 E-7 m is used in Young's experiment with the slits separated by a distance of 2.42 E-4 m. The screen is located at a distance from the slits of 12.0 m. Calculate the distance on the screen between the central bright fringe and the first bright fringe.