Dear student,

First of all you haven't mentioned that for what ideas you are asking that ncert 11th books are helpful.

Now, as per your profile I can assume that you are a medicine aspirant ( biology student ) of class 11th, then if you want to give class 11th exam, then yes, ncert will help you. Also if you are preparing to give the competitions like neet, etc. then also or will be helpful for you.
Because ncert is base book. And you have to read all the lines and solve all the questions which will be helpful for you in exams as well as in your gaining informations.