In practice, I don't know the IDs of the questions, but I can search for answers by given tag(s).

The problem is how to find (newly) accepted answers. The "activity time" does not work for this.

For example, see this question. It has key times like this:

Question:

      Last activity time: 22 Sep 2015 06:37:51 GMT

Accepted answer:

      Last activity time: 22 Sep 2015 06:37:51 GMT
      Accepted time:      Around 22 Sep 2015 17:00:00 GMT

The last activity time of question/answer is not changed when the answer is accepted.

So, how to monitor if an answer is accepted? The API routes only take creation time or last activity time.