Here are five reasons why people have no question after a talk.
The Elephant in the room. In some countries, the attendees may consider impolite to talk before a more senior person in the room does ( a dean, an official,…). That person may just be there for politeness, but not interest. Or that person may be unfamiliar with your topic and does not want to appear ignorant in from of the rest of the audience. The questions will come as soon as that person fires the first question or leaves the room. Stick around outside the presentation room for a real Q&A.
The unquestionable. Some questions would reveal things about the questioner that the questioner does not wish the rest of the audience to know. Alternatively, things you said may be so obvious and clear that nothing you said raises question. You stated unquestionable facts to an audience already convinced of the facts. Your presentation may not have been bad, but it probably was not useful.
The unknowledgeable. Some things you said during your presentation are blatantly wrong, and the audience is knowledgeable enough to know it. They could attack you, but in the process, would embarrass you. So they simply stay quiet, and leave. They were there to learn for an expert. You were not that person.
The arrogant. Alas, some presenters have a knack to make you feel out of place. They mention their elitist friends during the talk, say several times that only a minority of people are smart enough to understand the problem. And by the time the talk ends, you know you are part of the majority. They cocooned themselves away from any potential question. Withdrawn, stern face turned away from the audience as they gather their makeshift notes, their body language clearly communicate they have no inclination to answer any question.
The Vanishing. WAIT! Do not do your disappearing act, immediately closing any opportunity for questions with a lame statement like “I must have been very clear since you have no question”, and rushing off stage. The audience needs body language to be encouraged to ask questions, your warming smile will get anyone out of a state of permafrost, let it shine! Give it time to work its magic. Unfold your arms. Invite. Move towards the audience. and wait. Let the unbearable pressure of silence work its tongue loosening magic. But let that not be your tongue! It is the audience’s turn to speak.
The jargonaute. The jargonaute’s talk is for people from planet science. Unfathomable, undecipherable, impenetrable, it is not of our world. As minutes pass by, you discover that an abyss of ignorance separates you from the jargonaute. You want their knowledge, but it turns out to be your kryptonite. No question the jargonaute is an expert. No question!