In an experiment with a rectangular glass slab, a student observed that a ray of light incident at an angle of 55^∘ with the normal on one face of the slab, after refraction strikes the opposite face of the slab before emerging out into air making an angle of 40^∘ with the normal. Draw a labelled diagram to show the path of this ray. What value would you assign to the angle of refraction and angle of emergence?