wikipedia allows to copy contents from the site on any blog or article provided proper acknowledgment is done. Link to the original article satisfy this criteria. It also allows modification of the copied contents. Now the question is if I copy contents from wikipedia on my blog and modify it, will it be legal to put adsense on that page?
Well, I don't see why not. I am not an expert but I doubt you'd be violating the adsense TOC, and if Wikipedia doesn't specifically mention anything about ads, then I would just go for it.
when google looks at a copied material, it doesn;t look to see whether it was a legal copy or not. what is looks is the duplicate content. use it if you can modify it to a point where there is no way for google to identify duplicate content.
If they allows you to copy contents, then its ok. But, you will get penalized in SERP as it will count as duplicate content.
I don't expect much traffic from SE for a small blog. I shall drive targeted traffic using alternate methods. My only concern is whether it will be against TOS of adsense or wikipedia.