Question

Why are secondary maxima much weaker than the central maximum?

Options

• The secondary sources within the slit cease to be in phase

• All wavelets arrive in phase at each secondary maximum

• A significant portion of the slit still cancels out

• All path differences are zero at each secondary maximum

Answer 1

At a secondary maximum, a significant portion of the slit still cancels out. Consequently, its intensity is much lower than that of the central maximum.