Diffraction is observable when the opening is than the wavelength.
smaller
larger

The opening needs to be smaller

Explanation:

Diffraction can be observed when the light passes through a grid or an opening that has a width of about the same size or smaller than the wavelength of the light that is being used.

We need the opening to be smaller than the wavelength so the bean can be splitted and we are able to see diffraction.

ok

explanation:

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table