Shortest video on Youtube monetize

Hi all,

What's the shortest video on youtube you can monetize through Adsense? Because I have a bunch of 10 - 20 second video's and I want to find out if that's possible Google isn't clear about that and simply trying isn't an option because I have only one adsense account.

Have in mind that the content is unique and won't have any copyright.

youtube，adsense，Hello, I come from China, and our country is similar to the Youku, 56, there are a lot of this