If a international company uses same content across different top level domains(tlds) like uk, ca will it raise content duplication issue?
Duplicate content is always an issue, but according to this video it shouldn't hurt: http://www.seomoz.org/blog/whiteboard-friday-interview-with-googles-maile-ohye
Matt Cutts of Google answered this exact question just a couple of weeks ago. He said that it should not be a problem. http://www.youtube.com/watch?v=Ets7nHOV1Yo
Duplication of content can effect your ranking, at the same time you might be subjected to legal issues.
No. Never use same content in different domains. Because the biggest killer of copied content Panda Algorithm is killing such websites that have copied or low quality content.
The next update will target a common webmaster complaint related to the original Panda/Farmer update: sites that scrape and re-publish content and are out-ranking the original source of the content.