AΛA d sine/A Figure 14.3.2 Intensity as a function of dsin/ For small angle 0,using Eq.(14.2.7),the intensity can be rewritten as I=1o cos πd (14.2.24) Example 14.2:Intensity of Three-Slit Interference Suppose a monochromatic coherent source of light passes through three parallel slits, each separated by a distance d from its neighbor,as shown in Figure 14.3.3. S Figure 14.3.3 Three-slit interference. The waves have the same amplitude Eo and angular frequency @but a constant phase differenceφ=2πdsin0/λ. (a)Show that the intensity is -+2a0j (14.2.25) 14-1114-11 Figure 14.3.2 Intensity as a function of d sinθ / λ For small angle θ , using Eq. (14.2.7), the intensity can be rewritten as I = I0 cos2 πd λL y ⎛ ⎝ ⎜ ⎞ ⎠ ⎟ . (14.2.24) Example 14.2: Intensity of Three-Slit Interference Suppose a monochromatic coherent source of light passes through three parallel slits, each separated by a distance d from its neighbor, as shown in Figure 14.3.3. Figure 14.3.3 Three-slit interference. The waves have the same amplitude E0 and angular frequency ω , but a constant phase difference φ = 2π d sinθ / λ . (a) Show that the intensity is I = I0 9 1+ 2cos 2πd sinθ λ ⎛ ⎝ ⎜ ⎞ ⎠ ⎟ ⎡ ⎣ ⎢ ⎤ ⎦ ⎥ 2 , (14.2.25)