2. CD Pits [20 pts]. In a compact disc (CD), once the cutting edge of storing recorded music and information, interference of reflected light waves can be used to read encoded information. Light from a red laser () = 630 nm) is reflected from small pits in the CD, and waves from the bottom of a pit and the adjacent top edge interfere. The pits are covered with a layer of plastic so that surface scratches do not spoil the pits. If the index plastic filled of refraction of the plastic coating is n = 1.70, pit what minimum depth should a pit have to give destructive interference