There is no relationship between PR and Adsense earnings. PR depends mostly on the backlinks a site have.
Your site content and your targeted keyword are the two important things that we should consider rather than PR.Bcause increasing PR is not a matter now a days,so try to post nice niche with high and targeted keyword.
Higher PR page will have better positions in SERPs. Clicks generated thru organic traffic to the higher PR page may get higher revenue.