The best pro/research-grade models from Google and OpenAI now have little difficulty recognizing when they don't know how or can't find enough information to solve a given problem. The free chatbot models rarely will, though.

This seems true for info not in the question - eg. "Calculate the volume of a cylinder with height 10 meters".

However it is less true with info missing from the training data - ie. "I have a Diode marked UM16, what is the maximum current at 125C?"