"Is there garlic in the soup?"
Translation:Är det vitlök i soppan?
When you ask this question, you don't know if there is garlic in the soup or not. So you are not thinking of some specific garlic, just "garlic in general". Therefore it is indeterminate both in Swedish and English.
Yes, that's an accepted answer, though it would probably not be the most natural way to put it. But it's ok!