What is and amplification factor in pseudo-random generators?

I can’t seem to find an answer to this. For instance, I have this question:

Show that, if $ P=NP$ , there aren’t any pseudo-random generators (even with amplification factor $ n+1$ ).

My gut tells me this is because, in a world where $ P=NP$ , pretty much any process can be efficiently inverted so there aren’t one-way functions (which pseudo-random generators rely on).