Chapter 11.3, Problem 3cT

Coherent red light is incident on a mask with two very narrow slits a distance d apart. The photograph at right illustrates the pattern that appears on a distant screen.

On the photograph, label each of the maxima and minima with the corresponding value of $\Delta D_{\text{adj}}$ .

Suppose that a third slit were added to the mask so that adjacent slits were separated by the same distance d as before.

In the space provided above, sketch the pattern that you would expect to see on the same pan of the screen. On your sketch, clearly label each minimum and principal maximum with the corresponding value of $\Delta D_{\text{adj}}$ .

Ask a tutorial instructor for photographs that illustrate the patterns that appear on a distant screen when light is incident on two masks: one with two slits and one with three slits.