The lab experiment is repeated again with the same two glass plates and the same sodium lamp but with a different human hair. The space between the plates is filled with a transparent silicon grease that has n = 1.34. The glass plates each have refractive index 1.20. The separation between adjacent dark fringes is measured to be 0.770 mm. Calculate the diameter of the hair. (The wavelength emitted by the lamp is 589.3 nm.