Would "Is the water cold in the lake?" also be correct? I don't know if that would change the emphasis - there's no verb in the sentence so I can't tell.
That's OK too. I think they just followed the word order from the Hungarian sentence since it was possible to do so.
The grammaticaly correct way to say this is: "Hideg a víz a tóban?" This is coming from a native speaker.
Doesn't this change only the emphasis?
One question asks whether something is cold. That something is or is not cold is important.
And the other one lays the focus on the water. How is it, cold?
I don't know which does what...