text: physics problem? i just want to know that in some questions regarding contructive and destructive interference, sometimes it is not mentioned in bold whether the problem is with regard to constructive or destructive interference. how can you know whether the problem is with regard to either constructive or destructive? any specific words or any thing else??? constructive means, to build or put together, and destructive means, the act of destroying something.  when you are reading your questions, try to analyse whether the end result is a consruction or a product that has been destroyed.   i hope this helps good luck