I have created a new blog and created a adsense account for it.but during the adsense setup it asked for the Ad size and i selected A leaderboard ad. Similarly in Blogspot--->customize option there is another link specifying Adsense. So does both adsense things pay the same or are there any difference in income generated
They are the same - you can generate your ad code and paste it in blogger in the add html/javascript gadget or you can use the adsense gadget to add adsense to your blog. If you are using a different google account for adsense and the blog you will need to add your adsense publisher ID in the adsense gadget to use it.
Maybe there is, but google will catch you quickly and you will get banned - don't think about this at all.
You just started your blog and Adsense and thinking of cheating Google. That's really too bad to hear. You can earn good money without cheating also. Just put some efforts. And if you are here in DP and talking about such activity. You may first ban from DP and then from Google.