Anyone know if you can use this to send laptop screen (images/PDFs/PowerPoint) to a TV screen?
You can. I was down visiting a company we do business with recently, and the boy was using chromecast to show his whole laptop screen on the tv monitor in the same way an HDMI cable would (got the impression you could choose whether it reflects the whole screen or other options.. maybe just single presentation or something?).
It was a lot slower in reacting on screen when the boy was moving the mouse etc compared to the traditional wire method, so much so that he went back to a cable!! Not sure if this is the norm or was just our experience of it.