It depends on niche (topic), content and placement of ads. If every thing matches then you should be earning good. For example finance/insurance related niche can give you around 10$ per click easily.
Easily huh... LoL... that's the dreamers attitude and the reason behind so much spam on the net - it's not that simple.
It is possible to earn a huge money, but requires quite some work and time. You need one or more websites with alot of traffic. Besides that, your Adsense income is never certain, you never know what next month will bring you. I would rather see it as a part of a diversifiated income. www.techyv.com/questions/what-adsense-and-how-can-i-earn-it
No accurate way of answering your question as so many variables (site niche, site content, CTR, whether high paying field such as finance/Insurance/Debt/Medical etc.). Just to give you a rough idea - 250 visitors per day. Out of these, you receive between 3 - 5 clicks (3 - 5 clicks = around 2% which Google say is the average). For these clicks, you receive $0.10 per click (low - mid range click rate). So approx $0.40 per day or $12.00 over the month. As I said, too many variables but just a quick and dirty breakdown for you.
It depends on type of your blog. If your blog is about technology then google gives highest priority to technology sites then second priority gives to education blog but if your site is mix type then google will gives third priority so now you decide
Not really sure how much you will earn,but i will just consult my crystal ball and get back to you. Well after taking a look the crystal ball has mentioned the revenue that you could get and its $136.78 but that could well be wrong,it usually is