# Why does a “cavity with a hole” model of a black body not absorb/emit radiation larger than the size of the hole/cavity?

This wikipedia article on the "cavity with a hole" model of a black body says:

The hole is not quite a perfect black surface — in particular, if the wavelength of the incident radiation is longer than the diameter of the hole, part will be reflected. Similarly, even in perfect thermal equilibrium, the radiation inside a finite-sized cavity will not have an ideal Planck spectrum for wavelengths comparable to or larger than the size of the cavity.

So I have 2 questions.:

Why is it that light of a wavelength larger than the hole will be reflected?

Why are wavelengths larger than the size of the cavity not emitted?

The propagation of an EM wave through a small hole decays very quickly, like $$d^4$$, so while it can propagate it's very unlikely. Same principle that makes the microwave mesh a good way for us not to be microwaved too.