Question

What path difference between corresponding rays from the two equal halves of the slit causes them to cancel?

Options

• \[2\lambda\]

• \[\lambda\]

• \[0\]

• \[\frac{\lambda}{2}\]

Answer 1

Corresponding rays with a path difference of \[\frac{\lambda}{2}\] cancel by destructive interference. Pairing rays across the slit in this way produces a dark fringe.