[问答题]
White light strikes (a) a diffraction grating, and (b) a p c ltjat:,yw+zm4qhxj5s :3 q2rism. A38pt1b lvekv)04ewk 9pqh it- rainbow appears on a wall just below the direction of the horizontal incident beam in each case. What is the color of the top of the rainbow in each casekptvl19-v0 bqwe8t)pk 4hi3e? Explain.
