When you see instant replay in slow motion on TV, why do the lights flicker?

I'm watching the Yankees/Angels game right now and whenever they show a replay in slow motion, the lights in the stadium seem to flicker on and off very quickly. Is this really happening or is it an illusion?When you see instant replay in slow motion on TV, why do the lights flicker?Because they are displaying indvidual pictures at a slower rate than normal. Therefore appearing as a flashing motion.

pdd nos