Problem 18PE

Figure 27.56 shows a double slit located a distance x from a screen, with the distance from the center of the screen given by y . When the distance d between the slits is relatively large, there will be numerous bright spots, called fringes. Show that, for small angles (where sin θ ≈ θ , with θ in radians), the distance between fringes is given by Δy = xλ / d .

Solution 18PE

= is proved.