Raise must have an object, as it is a transitive verb. It is a regular verb; its three forms are raise, raised, raised:
Raise your hand if you know the answer.
Our favourite restaurant has raised its prices again. It’s getting very expensive.
Rise does not take an object, as it is an intransitive verb. It is an irregular verb; its three forms are rise, rose, risen:
The sun rose at 5.30 this morning.
Rents have risen sharply in this part of town.
