Depends on the niche. If the niche is specific lets say you have a world of warcraft video, you will most likely get gaming ads on your video. And they generally have high cpc. So cpc is cost per click. If you have a money making video you will most likely get credit card ads etc. They too, I believe, have decent cpc. And videos to do with computers etc you get the idea.
I dont really know alot about adesnse but Ihope what i said was right and helpful!