Definition: Rhetorical; a question asked to produce an effect, not to elicit information.
Skills of being a Mother #58:
The rhetorical question.
Usage: "Have you washed your hands?"
This is rhetorical because as a Mother you know hands have not been washed with both soap and water.
Alternate usages:
"Is this your underwear I just found on the floor?"
or, "Was poking your sister in the eye with your toothbrush really a good idea?"
and the classic, "Would you like me to do that to you?"