Phrasal verb: Wake (sb) (up)

Hi all,

Please choose “wake” or “wake up”. Are they interchangeable?

1.What time do you usually wake/wake up in the morning?
2.I always wake/wake up early in the summer.
3.Wake!/Wake up! It’s 11 o’clock.
4. He woke /woke up to find himself alone in the house.
5.Try not to wake the baby.
Try not to wake the baby up.
6. It was woken/woken up by the sound of somebody moving around.

If “wake” and “wake up” are interchangeable, do you think “up” is expletive? If not, please explain me the difference btw “wake” and “wake up”, especially the meaning of “up” in these cases.

“Up” here is adverb?


All sound more conversational with ‘up’; only #3 sounds odd without ‘up’. I see no substantive difference otherwise.