他在电视上泼了点儿水。The sentence itself is grammar correct. But there is not context for this single sentence, it may cause confusion. You could possibly say '他不小心在电视上泼了点儿水' By adding '不小心'(by accident). You can make the sentense sounds more logical and meaningful.
我在电视上看到一部很好看的电影
I have seen a really good movie on TV