Suppose if around 50 words of content is copied from one of the inner pages of my website to homepage and i have placed read more option under that section. Will google treat it as copied content or not?
No, teasers are not considered as pieces of duplicate content...says Matt Cutts. Here, check this: http://www.youtube.com/watch?v=GgmXYZOBVJM&feature=related
If we have use some detail for beginning and then give reference to the original one , then it not consider as the copied one.
No, Google will not treat that as duplicate content. The following article on Google Webmaster about duplicate content will help you identify what is bad duplicate and not.
Copied content means, If you copy content from other website and add in your website, then your website will identify as a copied contents.
In actual this will be duplicate content, but Google will not harm your website for this because it is your website's own content and you have not copied it from somewhere else.
Google will not treat that as duplicate content. please check google guideline on you google webmaster tools
Google will not give value for copied content, but website owner can take legal action if you copied some content from websites.