a For a given wavelength L what is the maximum slit width fo

(a) For a given wavelength, L, what is the maximum slit width for which there will be no diffraction minima? Use L for the wavelength.

(b) What is the minimum slit width so that no visible light exhibits a diffraction minimum? (Visible light has wavelengths from 400 nm to 750 nm.)

Solution

There will be no diffraction minima if the angle for the first minimum is greater than 90°

a sin theta = m * lambda

a_max sin 90 = 1 * lambda

a_max = lambda

----------------------------------------------

750 nm