"TV wasn't developed to show film but to show live action captured by a video camera. They needed a way to have both the TV camera and all TV sets to operate at the same frame rate. The TV scan rate is derived from the power line frequency (60 Hz in the US, 50 Hz in the UK) which is very stable. There was no easy way to sync a TV scan with the broadcast if the frequency was some odd number like 20 to 24 frames/sec. "

I think I understand. Does this mean that the TV in the US, being 60 Hz, is closer to reproducing the frames/sec in the theaters? Is film projected at different f/sec in different countries? Why does the UK use 50 Hz?
Sorry for all these questions. I am never afraid to show my ignorance of a subject!