Video and Search Engine Optimization

Does the video have to be a certain length for it to be used for SEO, which means Search Engine Optimization?

No. What it has to do is answer a question that somebody is typing into the search engine. If you can answer that question in ten seconds, then that's the length of your video. So if you ramble on, a lot of times people won't wait to get the answer. So get to it as quickly as you can.

Yes.