Questions about example sentences with, and the definition and usage of "Obligatoire"

A: La traduction littérale est "obligatory", mais cela manque de naturel. On dit plutôt "compulsory", "mandatory", "inescapable" etc. selon le contexte.

Exemples :
1. Le port du casque de moto est obligatoire en Pennsylvanie = Wearing a motorcycle helmet is mandatory in Pennsylvania.
2. Le prénom de cette petite fille devra obligatoirement commencer par la lettre N ! = This little girl's name must necessarily begin with the letter N!

A: "É obrigatório?"
"Isto é obrigatório?"
"Isso é obrigatório?"

A: If you say "is it mandatory?" that sounds natural