Learn English – A question asked in order to expose ignorance

When someone asks a question by stating a negative fact, it would seem logical to answer affirmatively because the fact is true. However, it is more common to answer negatively to confirm the negativity.

Mom: You didn't finish your homework, did you?

You: No, I didn't

Mom: You finished your homework, didn't you?

You: No, I didn't

In both cases the Mom wants to know about the status of the homework and the questions are equivalent to

Mom: Did you finish your homework?

(The reason to use the tag form is to communicate the speaker's assumptions or surprise or expectations about the homework rather than just asking for a status update).

There is more explanation about this here.

The answer to what type if question this is, in the sense that you are asking it, depends on how much information related to the answer the asker has.

If the asker has little information then this can be considered a closed, factual question.

If the asker has enough information that he should be able to surmise the answer this could be a rhetorical question.

Using the example above of a sitcom, if the speaker is speaking to one other person, and that person's face suddenly looks surprised while looking in a direction behind the speaker, that's probably not enough information to make the question rhetorical, so it's a simple closed, factual question.

If, on the other hand, the person listening puts one hand over his mouth, and with the other points rapidly over the speaker's shoulder, or, alternatively, if the person being spoken about let's out a loud "harrumph" then either of these could be enough information to make the question rhetorical.