I think you are supposed to use adsense code on the site or blog for which it has been approved.

You can use it on all of your sites, but remember if ANY of your sites fall foul of their rules you can expect to have your AdSense account permanently banned. Swat up on the rules and build your sites to conform to them, you'll have no problems that way.

[DELETED]

When one of your websites are approved, then submitting and approving your other websites is not needed and you can place your ad codes in any website you want but you should be careful to place adsense ads only on websites that don't violate Google adsense terms.

No you dont submit a new application for every site

one account and you can have unlimited sites

paul

You only need one account, but I recommend creating different codes for each website.

That way you can see not only which website is getting more clicks and higher CPCs, but also where they are clicking on your website.