can i ask how much we can earn from impresion?

Google don't allow it's users to discuss earnings in relation to impressions..

And even if they did, nobody could tell you.
It depends entirely on what adverts get displyed on your site. (and other factors)

(if that is what you meant)

There are 2 types of ads. CPC and CPM.

For CPC ad, you got paid only when someone click on it. The pay per click can vary from 0.0x to x.00... all depends on the associated keywords.

For CPM ad, you got paid for every impression. When advertisers put ads on your site called site targeting ads, they will be in CPM basis. For one of our site, the CPM is around 0.x per 1000 impression. This can vary depending on your site topic.