Chapter 25.1, Problem 3gTH

Determine the angles for which there will be nodal lines and lines of maximum constructive interference for the case of two sources in phase, a distance l.5λ apart.

1. Use your results to draw accurate nodal lines and lines of maximum constructive interference on the diagram at right.
2. Label each line from part i with the corresponding value of $\Delta D$ , θ, and $\Delta \phi$ , where $\Delta \phi$ is the phase difference between the waves.
3. If the distance between the sources were increased, would the angle θ to the first nodal line increase, decrease, or stay the same? Explain your reasoning.