which Topic more profitable for placing adsense. i have many different site with different topics and i want to place adsense on few of them so which topic is more porfitable.
I would say ... that it is quality of your site that matters.... All are equally good. More the traffic ..more your adsense earnings.
The best paying ads are those from advertisers that are actually selling something, preferably something expensive. For example, ads for Dell computers will be worth something, yet ads for 'free stuff' won't. Financial and medical products appear to do well for that reason. However, aiming for the top paying keywords isn't necessarily going to get you the best traffic. www.symbiotic.com can be useful for evaluating the value of keywords... Cryo.
I guess it kind'off depends on what keywords you`re targetting there, but off the top of my head I can tell you that free wallpapers will probably pay pennies. Online education I would think it's worth more, but again, you should check with overture what others bid for the keywords you`re targetting.