If a room were completely dark, could you see your hand? would you be able to see a tv screen? is there a difference?

Maybe, just maybe, in a couple of minutes you'll get used to it. And you might then be able to see the outline of your hand. TV's are usually black like pitch, black. I'd say since you've seen that hand a couple of times maybe it'll see seen more visibly.
Sorry, if it's incorrect.