Professor So-and-So?

My Commerce professor always speaks as if we'd call her by her first name in her examples: eg. "but you might say to me, Rita? Why is this a viable option? I'll explain then that this way..." Although no one ever calls her by her first name when addressing her, it's always just Prof. <last name>.

Some professors are spoken to with "Prof. <last name>" while others seem to have their names better suited if they are said as "Dr. <last name>" (such as our psych professor who only visited us once ever and left us to learn from his video lectures). It feels awkward and rude to me to dare using the first name only when addressing these intelligent people.

Jam it back in, in the dark.