De or het perioptica?

The correct Dutch article is:

de perioptica

Rule Words ending in -ica: usually de. See the rule
Meaning (Dutch) (optica) leer van de straalbreking en terugkaatsing aan de oppervlakte van de lichamen

How to use perioptica

the periopticade perioptica
this periopticadeze perioptica
that periopticadie perioptica
our periopticaonze perioptica
your periopticajouw perioptica
every periopticaelke perioptica
which perioptica?welke perioptica?
a big perioptica / the big periopticaeen grote perioptica, de grote perioptica

Meaning, plural, diminutive, pronunciation and translations: WikiWoordenboek (Dutch Wiktionary) (CC BY-SA 4.0). Example sentences: Tatoeba (CC BY 2.0 FR).