Its depends on your niche. If you choose high paying keywords then you get more $ for it . One of the example is " personal injury"
Yeah, those are the main facts for a high CPC. There are keywords CPC worth around 20-50$ such as car/auto insurance related keywords.
Some niche keywords site can gain over 1 USD a click occasionally.Sometimes it happened to my japanese and loan classifieds.
Pretty easy here to figure it out. Low paying clicks around 10c or less can usually be attributed to only 2 things. The clicks are very low converting clicks (e.g. the people who are clicking the ads tend to not take the action on the page google adsense send them to) or the niche itself is a very low paying paying with the adwords advertisers are paying such a low amount that the maximum amount adsense can pay is that amount. Yes you do get penalised by google with reduced amounts per click if your conversation rate is low (a sign that your traffic is not very targeted to the ads). Conversely $5 in 5 clicks means the opposite. Quality of content also makes a big difference here as well. I've had adsense clicks in big niches (Internet Marketing and Debt Consolidation pay $10 + per click).