How do I get only specific response from ChatGPT?

Hi there! I want to add a chat bot in our web app. Our app is based on solar energy. So chat bot will answer only if the question is related to solar otherwise it will say “I don’t know”.

For Example:
Q: What is solar?
A: “Solar” is a term commonly used to refer to the sun or anything related to it. It is derived from the
Latin word “sol,” which means sun.
Q: How to prepare for an interview?
A: I don’t know.