A very narrow beam of light containing red (660 nm) and blue (470 nm) wavelengths travels from air through a 0.84 m thick flat block of crown glass and back to air again. The beam strikes at a 30.0 incident angle. By what distance (in mm) perpendicular to their direction of travel are the red and blue beams separated when they emerge?

The index of refraction for = 660 nm is 1.512 and the index of refraction for = 470 nm is 1.524