Question

Why is \[n=0\] excluded from the condition for minima?

Options

• It corresponds to a secondary maximum of decreasing intensity

• It marks the first dark fringe on either side

• It corresponds to the central maximum, not a minimum

• It gives a path difference of \[\frac{\lambda}{2}\] between paired rays

Answer 1

For \[n=0\], the condition gives \[\theta=0\], the direction of the central maximum. The wavelets arrive in phase there, so this position is not a minimum.