A light beam strikes a thick glass window that is 1.3 cm thick and has an index of refraction of 1.4. The light strikes the window at an angle of 30o to the normal. Assuming the two sides of the glass are perfectly parallel, the ray will bend at both surfaces oppositely continuing at 30o. However, the path through the glass will be at an angle causing the ray to offset a bit from its original path. What is the offset?