What determines if a EM wave can go through a wall? First thought

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>>9131679
The absorption spectrum doesn't have to be monotone.

>>9131811
but why

>>9131834
Different ways of interaction between light and matter. EM waves can stimulate oscillations and be converted into heat for example.

>But why
Stop asking like a two year old and google that shit

>>9131834
Simple, but not entirely correct explanation ;
EM waves are absorbed/reflected/ignored by molecule depending on their frequency and factor such as form, mass, proper constants and stuff of the molecule, but also sometimes crystalline structure and stuff.
So, depending on freq, some.might pass and other not.

RESONANCE