Red laser light (A = 680nm) shines upon two slits separated by a distance d = 125um. A screen is set up L = 1m away (see figure). For this problem, neglect the width of the individual slits and treat them like point sources. o'I | y =0 e L (a) What is the location of the first dark spot for y > 0%' (b) A piece of glass (n = 1.5) is placed over one slit (see figure). How thick must the glass be such that a dark spot appears aty = 0? dI y=0 (c) (5 points) The slit without the glass is now covered so that no light can travel through it. What happens to the light intensity at y = 0? Does it increase, decrease, or stay the same? Explain