What is the difference between んだ/のだ being conjugated and it being added to the end of a verb or adjective?


I was reading Tae Kim and I came across two different ways of using んだ, one
was to add it to a conjugated verb and the other was to conjugate the んだ
itself. Would this affect the meaning of the sentence, or are these simply two
different ways of saying the same thing.

For example does 学生なんじゃない and 学生じゃないんだ mean the same thing?

