Absolutely. I have no problems with lots of questions and even encourage it. I also encourage that the child should take some time to learn and explore the problem themselves.

I am also a firm believer that a well formed question is sometimes more important than the answer they think they need. Teaching a child to ask the correct questions will fiter out 90% of the noise, I have found.

I also happen to be an engineer and am really good at lecturing on topics I enjoy. So, unless they want to be stuck for a couple of hours learning all the nuances of any particular subject, they need to come to me prepared.

Another method I have found effective is to point the child in the direction of the subject they are wanting to know about. So, if they ask me a question about one topic, I give them 10 research areas to explore first so they can start to understand my answers.

This all boils down to teaching a child how to teach themselves.