I have written a lot about pausing in the past. Here are some additional insights about the pause as it relates to humor from well-know speaking expert Tom Antion.

“In joke telling, a pause just before and just after your punch line sets it apart from the setup of the joke and gives the audience a chance to laugh. Absolutely do not continue to talk when laughter is expected. Laughter is hard to get and easy to discourage. Hold eye contact a little bit longer than you think you should when delivering punch lines because time is hard to judge when you are pumped-up for a presentation.
The size of your audience will affect your timing. Your presentation will take less time to deliver to smaller audiences. Smaller audiences should mean quicker laughter. Conversely, presentations will take longer for extremely large crowds. Your pauses will be longer to compensate for the wave effect created because of the physical distance between you and the back row of the audience.” from Wake ‘em Up Business Presentations