What is what episode does iris find out that barry is the flash?

In the TV show "The Flash," Iris West (played by Candice Patton) first learns that Barry Allen (Grant Gustin) is the Flash in Season 1, Episode 13, titled "The Nuclear Man." In this episode, Iris witnesses Barry using his super speed abilities to save her from a burning building. She confronts him about his secret identity, and Barry reveals the truth to her. This revelation marks a significant turning point in their relationship and sets the stage for future developments in the series.