A monochromatic light source is incident on the first screen that contains a slit So.The emerging light then arrives at the second screen which has two parallel slits S,and S,. which serve as the sources of coherent light.The light waves emerging from the two slits then interfere and form an interference pattern on the viewing screen.The bright bands (fringes)correspond to interference maxima,and the dark band interference minima. Figure 14.2.2 illustrates ways in which the waves could combine to interfere constructively or destructively. P Figure 14.2.2 Constructive interference (a)at P,and (b)at P.(c)Destructive interference at B. The geometry of the double-slit interference is shown in the Figure 14.2.3. S Figure 14.2.3 Double-slit experiment Consider light that falls on the screen at a point P a distance y from the point O that lies on the screen a perpendicular distance L from the double-slit system.A distance d separates the two slits.The light from slit 2 will travel an extra distance =,-n to the 14-514-5 A monochromatic light source is incident on the first screen that contains a slit S0 . The emerging light then arrives at the second screen which has two parallel slits S1 and S2 . which serve as the sources of coherent light. The light waves emerging from the two slits then interfere and form an interference pattern on the viewing screen. The bright bands (fringes) correspond to interference maxima, and the dark band interference minima. Figure 14.2.2 illustrates ways in which the waves could combine to interfere constructively or destructively. Figure 14.2.2 Constructive interference (a) at P , and (b) at P1 . (c) Destructive interference at P2 . The geometry of the double-slit interference is shown in the Figure 14.2.3. Figure 14.2.3 Double-slit experiment Consider light that falls on the screen at a point P a distance y from the point O that lies on the screen a perpendicular distance L from the double-slit system. A distance d separates the two slits. The light from slit 2 will travel an extra distance 2 1 δ = r − r to the